You can spend thousands of dollars on components when building a PC, but it won’t boot without an operating system (OS). Linux is a viable option, but most people prefer Windows because it runs all of their favorite software, including the latest games. And for those who were still holding on, Windows 7 has officially reached its end of life, meaning it won’t get any more support or security updates. Fortunately, you can get Windows 10 for free or cheap, if you know where to look.

Getting hold of the Windows installer is as easy as visiting support.microsoft.com. Whether you’ve paid for Windows 10 already or not, Microsoft lets anyone download a Windows 10 ISO file and burn it to a DVD, or create installation media on a USB drive for free. Once that’s done, you can boot from your installation media and load Windows 10 onto your PC. During the installation process, Microsoft asks for an activation key. You can skip it, but eventually, Windows will start alerting you that your install isn’t activated.

There are many ways to get a Windows 10 activation / product key, and they range in price from completely free to $309 (£339, $340 AU), depending on which flavor of Windows 10 you want. You can of course buy a key from Microsoft online, but there are other websites selling Windows 10 keys for less. There’s also the option of downloading Windows 10 without a key and never activating the OS. But what, if anything, are you missing out if you don’t activate Windows 10? And does your carefully crafted rig face any risks?

Below we outline the top ways you can get Windows 10 — from the cheapest to most expensive — and the downsides of each option.

Upgrade From Windows 7 or 8 to Windows 10: Free

Nothing’s cheaper than free. If you’re looking for Windows 10 Home, or even Windows 10 Pro, it’s possible to get Windows 10 for free onto your PC. If you already have a Windows 7, 8 or 8.1 a software/product key, you can upgrade to Windows 10 for free. You activate it by using the key from one of those older OSes. But note that a key can only be used on one PC at a time, so if you use that key for a new PC build, any other PC running that key is out of luck.

To do this with a Windows 10 compatible PC (after backing up your important data, of course) download Windows 10. When asked, select “Upgrade this PC now.” Note that if you’ve recently changed your PC’s hardware, such as the motherboard, Windows may not find the license for you device. That means you’ll have to reactive the OS. Here are Microsoft’s instructions for reactivating Windows 10 after changing PC hardware. 

Downsides of Upgrading From Windows 7 or 8

When using an older Windows key to activate Windows 10, you may run into complications if Microsoft isn’t sure whether you’re eligible to update or not. In that case, you’d have to call a number and go through a process of entering your key and getting a code. But that seems to be happening less in recent months and years.

Don’t Activate Windows: Free

If you don’t have a valid key, you can still use Windows 10 for free on your PC even if you don’t activate the OS. I have colleagues who have used non-activated versions of Windows for years without Microsoft ever shutting it down. In this way, you can have Windows 10 Home or Pro running on your PC nearly flawlessly. Nearly…

Downsides of Not Activating Windows

“If the user [installs Windows 10] before activating Windows, they will see an ‘Activate Windows’ watermark on their desktop, as well an experience a limit on Windows 10 personalization options,” Microsoft told Tom’s Hardware in a statement.

Microsoft brands PCs running an unactivated version of Windows 10 with a watermark in the bottom-right corner of the screen. A Microsoft spokesperson told me that activating Windows 10 ensures you have a legitimate copy of Windows 10, and the watermark is an attempt to alert consumers that their version could be false. However, if you downloaded your ISO directly from Microsoft, there’s no way your copy can be a fake.

If you don’t activate Windows 10, you won’t be able to change Personalization options in the Settings menu. That means you can’t choose personal desktop wallpapers, slideshow backgrounds, Start, taskbar, Action Center or title bar colors, light or dark color schemes, font choices or lock screen options.

The lack of custom aesthetics can be a downer, especially if you like to liven things up by changing colors and images. However, we checked, and you can still change your wallpaper if you right-click an image from the web or a personal photo and set it as your wallpaper. And if you have a wallpaper tied to your Microsoft account, it will appear if you sign into Windows with that account.

Unsurprisingly, Microsoft won’t offer you any Windows 10 technical support if you don’t activate the OS. If you call or chat with their techs, they’ll start off by asking you for your key, and you’ll have no response.

Use the Microsoft Student Discount: Free

Microsoft offers students attending certain universities and high schools the ability to get Windows 10 for free by allowing them to activate Windows 10 Education for free. Meanwhile, teachers can get Windows 10 Education for $14.99. You can see if your school is eligible and download your free Windows 10 key here. The key is yours even after you graduate.

But is Windows 10 Education any different from Windows 10 Home? It’s actually better. Windows 10 Education is the same as Windows 10 Enterprise, which Microsoft calls the most robust version of Windows 10. The OS has features targeting security, device control and management and deployment that Windows 10 Home lacks. Unlike Windows 10 Home, Windows 10 Education has client and host remote desktop and remote app i(nstead of client only), Hyper-V (Microsoft’s hypervisor) and extra apps, like AppLocker and BitLocker. Although, it’s likely you won’t ever use any of those bonus features.

If you’re not currently a student but happen to have a .edu email, we don’t recommend scamming the system. In addition to ethical concerns, if you get caught, Microsoft can make you pay up anyway. “False representations of eligibility voids this offer, and Microsoft reserves the right to collect the full price of product(s) ordered,” Microsoft’s policy states.

Downsides of Using the Microsoft Student Discount

If your school is eligible for the discount, there isn’t really a downside to this method of procuring Windows 10 free. Not all colleges / high schools have it, and you may need to make a special user account to download it. But if you can score Windows 10 Education for free, we don’t see any reason not to.

Buy a Cheap Windows 10 Key From a Third-Party Seller: Around $30

If you can’t stand living with the scarlet letter of an eternal watermark or want the comfort of knowing Microsoft won’t disown your PC’s OS should you call for help, you’ll have to buy a Windows 10 key. And while some turn to Microsoft for this purchase, there are third-party websites selling keys for much cheaper than Microsoft. For example, at the time of writing, Kinguin sells Windows 10 Home for about $40, Amazon charges $129.99, Newegg’s pushing it for $89.99 and even Walmart has it for $99.95, as well as a Pro OEM version .

Now, let’s address the elephant in the room. While we can’t vouch for all of them, websites selling lower-priced Windows keys are likely selling legitimate codes. One popular site, Kinguin, has 37 merchants worldwide selling Windows keys. Mark Jordan, Kinguin’s VP of communications, told me that their merchants acquire the codes from wholesalers who have surplus copies of Windows they don’t need.

“It’s not a gray market. It would be like buying Adidas or Puma or Nike from a discounter, from TJ Maxx,” Jordan said. “There are no legal issues with buying it from us. It’s just another marketplace.”

According to Jordan, Kinguin’s merchants have sold “several hundred thousand” keys and are not one-time sellers posting listings for codes they don’t want. As part of its fraud protection, a Kinguin employee randomly buys a key “every now and then” to make sure they’re legitimate, he said. Jordan added that it’s rare for a customer to get a key that’s been resold, but if they did, customer support would help them get a new one for free.

“If there’s ever a problem with a key being already activated or something like that, our customer support team helps you get a new key… And that merchant would be in deep trouble, so they are very careful with it,” Jordan said. 

It’s worth noting that we’ve encountered reports of customer dissatisfaction, including from users who wanted a specific type of key (like non-OEM only), ended up with something different (like an OEM version) and could only get a refund, rather than the type of key they originally tried to buy.  

You’ll have to enter a key to activate Windows, but you won’t have a problem doing that if you bought your key from a place like Kinguin (or Amazon, Newegg, etc.). In fact, Microsoft still offers 24/7 technical support online and via phone even if you got your Windows 10 key from somewhere other than Microsoft.

If you do opt to get your key for less, make sure it’s from a legitimate site. A hint will be if that key is too cheap — i.e. free or close to free. And, as with anything else, if you haven’t heard of a seller, check their ratings or go elsewhere.

No matter where you get your product key, you shouldn’t download Windows 10 from anyone besides Microsoft. As noted on Microsoft’s website: “When buying Microsoft software as a digital download, we recommend that you avoid auction sites and peer-to-peer (P2P) file sharing sites. At the moment there are a limited number of sites where you can legally purchase digital downloads of Microsoft software.”

“Genuine Windows is published by Microsoft, properly licensed and supported by Microsoft or a trusted partner. Non-genuine software results in a higher risk of malware, fraud, public exposure of your personal information and a higher risk for poor performance or feature malfunctions,” Microsoft added in a statement to Tom’s Hardware.

Downsides of Cheap Keys

These non-Microsoft websites have varying return policies for software key purchases. While Kinguin seems to have an open return policy, 

Meanwhile, Amazon and Newegg both have no-refund policies for software keys. Amazon claims all keys sold on its site are genuine, and any gripes you have with your key must be handled by the individual vendors. If a key you bought from Newegg doesn’t work, you’ll have to contact Newegg’s product support team to get a new key.

Still, most, if not all, sites seem willing to accommodate you should you get a key that’s already been used or doesn’t work. Again, just make sure you’re buying your key from a legitimate source. For that reason we don’t recommend buying Windows 10 keys from individual sellers (or illegally).

This final downside is only applicable if you want to equip your PC with Windows 10 Pro for Workstations. While I was able to find Windows 10 Home on a number of genuine key-selling websites and Windows 10 Pro on some (although fewer) websites, I couldn’t find a place to download a key for Windows 10 Pro for Workstations anywhere besides Microsoft (Amazon sells it to ship for $293.83). The most advanced and pricey ($309) member of the Windows 10 clan, Windows 10 Pro for Workstations offers “support for the next generation of PC hardware, up to four CPUs and 6TB of memory,” according to Microsoft’s website. But it’s unlikely you’ll need the juggernaut of Windows 10 for your personal machine.

Buy a Windows Key From Microsoft: $139+ 

Want a version of Windows 10 where you can enjoy dynamic slideshows on your home screen and vibrant red, green, pink, or purple taskbars? Do you enjoy the thrills of a watermark-free screen and the comfort of knowing you can call Microsoft support if you have any problems? Then you need a key, which, as discussed, you can get from various retailers. But if you want to avoid any chance of getting an unusable key or want the guaranteed ability to get a full refund even if there’s no problem with the key, your best bet is buying from Microsoft.

In addition to selling keys for Windows 10 Home and Pro, Microsoft is the only place you can get a key for Windows 10 Pro for Workstations. Additionally, Microsoft offers the Assure Software Support Plan for an extra $99 (£95/ AU$120). This plan is valid for a year after activating Windows 10. It’s applicable for up to five devices and entitles you to online and phone support and one-on-one in-store training. One caveat: Microsoft says the plan is “for purchase and activation only in the region in which it was acquired.”

Downsides of Buying from Microsoft

Microsoft charges the most for Windows 10 keys. Windows 10 Home goes for $139 (£119.99 / AU$225), while Pro is $199.99 (£219.99 /AU$339). Despite these high prices, you’re still getting the same OS as if you bought it from somewhere cheaper, and it’s still only usable for one PC.

Plus, the premium price doesn’t entitle you to any support perks. Microsoft’s 24/7 basic phone and online support is available to anyone with a Windows 10 key, even those who didn’t get it from Microsoft. After already investing time and money building a PC , it can be difficult to convince yourself to spend over $100 for an OS that you can get with the same specs and support for cheaper.

What’s the Best Way to Get Windows 10? 

If you have an old Windows key you can get Windows 10 free by carrying that key over from a previous build — that’s your best option. 

If you don’t have a key on hand, you need to decide whether you’re comfortable using an unactivated version of Windows 10, which limits your customization options, has an ugly watermark and leaves you ineligible for Microsoft support. Many would argue that downloading Windows without paying for or already owning a product key is ethically wrong. That said, Microsoft has made this process easier over various Windows iterations and lessened the limitations and nagging that happens when you don’t activate. The company isn’t trying to close this loophole, probably because it’s more interested in driving user numbers. I’ve even seen well-known vendors and Microsoft partners do press presentations with watermarks on their desktop.

If you must buy a Windows 10 key, you can save a lot with a low-cost seller such as Kinguin, although customer service may be lacking. Microsoft’s price is astronomically high and doesn’t offer any significant benefits. You can save $100 or more by buying a key from one of these third-party sites, which is money you can spend on one of the best graphics cards, a roomier SSD, or a few AAA games for your new PC.

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