It seems like Microsoft is hitting the nail with Windows only every other version. So it's understandable that, if you're upgrading from Windows XP or looking for a new computer, you want to go for Windows 7 rather than Windows 8.

Thing is, Microsoft doesn't directly sell Windows 7 anymore. Here's what you can do so you're running a legal copy of Windows 7.

Is Your Hardware Compatible With Windows 7?

Before you make the final decision to upgrade, it's important to ensure that your hardware will be compatible with the new operating system.

To check, all you have to do is run the Windows 7 Upgrade Advisor. Our upgrade guide demonstrates the process and helps you understand each step. If the advisor gives you the green light, then you shouldn't have anything to worry about.

Transferring Windows 7 From An Old Computer To New Hardware

If you already have an old computer that runs Windows 7, and you want to move it to a new computer, you'll need to figure out whether you're running an OEM version or a retail version.

If you bought the computer and it already came with Windows 7, then it's most likely an OEM version. This version only works for one computer and cannot be transferred -- although hardware upgrades are allowed as long as they're not drastic enough for Windows to think it's running on a different computer.

If you installed Windows 7 yourself (meaning you bought the boxed copy), then you're most likely running the retail version. This version can be transferred to other computers, so you'll have to uninstall it from the old computer before installing it on the new one.

If you run into any issues while transferring your copy of Windows 7, we have articles that can help make your system genuine again (which is also a common issue after a hardware upgrade), help you recover your serial number, and help you determine when it's OK to borrow or download a Windows installation disk.

Online Retailers

If you plan on sticking with your current machine, getting an OEM version of Windows 7 is the way to go. Not only are OEM versions the only Windows 7 licenses still being sold, but they're usually found at all online electronics retailers such as Amazon, NewEgg, TigerDirect, and more with the notable exclusion of Microsoft itself.

Don't worry though -- all of these licenses are somewhat legal and they do work.

I do say that they're only somewhat legal because the Microsoft EULA states that the OEM version is reserved for system builders who want to sell a complete systems. Even professionals (and our own readers) aren't in total agreement about how legal this is for traditional end users, and to make matters worse, various places on Microsoft's website offer differing information. However, Microsoft isn't going to check up on you to see whether you built the computer yourself or whether you sold it to someone else, so you should be fine using this method.

One thing I do have to bring up is that OEM licenses aren't as flexible as retail licenses. With an OEM license, you can only activate it on the same computer with unchanged hardware. If you choose to replace any hardware in your computer, it may require another authentication that may end up not going through.

Second-Hand Sites Like eBay

If you need more flexibility than an OEM version of Windows 7 will offer, you can try to get a second-hand retail copy of Windows 7 from websites like eBay. At the time of writing this article, I even found a handful of auctions for copies of Windows 3.1 and Windows 95. Moreover, some professional sellers have new copies of Windows 7 at hand, which makes obtaining a copy easier.

You can save money when buying from individuals, but when it comes to software, you have to be very careful. You don't know how many times the previous owner used the license and keys may end up not working.

You should be safe if you happen to come across a sealed/wrapped copy of Windows 7, as that implies the key was never used, but those are rare to come across in private auctions. Moreover, you will most likely pay a higher price for unopened boxes compared to open boxes, but having that peace of mind is something I'd pay extra for.

Out of all the options available in this article, going for second-hand copies is the cheapest option as even the full retail versions found on eBay cost approximately the same or less as the OEM versions from online retailers.

Get A New PC With Windows 7

Finally, if you can't get Windows 7 as a standalone, you can try to buy a new PC that comes preinstalled with Windows 7. There are plenty of brands and online retailers that let you shop for computers with certain criteria, including which operating system is installed on it. If you find this option, just check any Windows 7 editions you're interested in.

If you're looking at a favorite brand, but don't see any available with Windows 7, you could potentially check out their section for business computers. Since businesses are holding on to Windows 7 for dear life, the chances of finding a Windows 7 PC here will be higher.

Having to narrow down your choices due to the operating system makes shopping for a computer a bit more difficult. You'll end up paying a lot more using this method since you're buying an entirely new computer rather than just the operating system. But if you're really locked in on using Windows 7, then doing so may be worth it.

Conclusion

Despite Microsoft discontinuing the sale of Windows 7, it really isn't that hard to get a legitimate copy of Windows 7. If you're wanting to save some money, do some research before you buy a product key; otherwise, just nab an OEM copy from an online retailer or get a retail version from a professional eBay seller.

Any other places to get Windows 7 product keys? What are the cheapest options you've found? Let us know in the comments!