You can reinstall Windows from scratch using the product key that came with your PC, but you’ll have to find installation media yourself. Microsoft offers free Windows ISO files — if you know where to look.
These tricks let you reinstall Windows without visiting a shady BitTorrent site and downloading ISOs that may be filled with malware. These links give you official installation media straight from Microsoft.
Note: depending on the OEM version of Windows that you are running, you will sometimes have an issue using the OEM key with a retail version of Windows, but you can always install and then call Microsoft and get them to straighten it out and allow your copy to activate. The most important thing is that you have a valid license key.
Note: We’ve been updating this article with every new release and now we’re updating for Windows 10.
Download Windows 10 ISO Image
Anybody can grab Windows 10 directly from Microsoft’s web site as of right now.
Windows 7 ISO files are available for download from Digital River, an officially licensed distributor of Microsoft software. These are the same ISO files you’d get if you purchased a digital copy of Windows 7 online.
This isn’t an officially supported way to get Windows 7 installation media — Microsoft won’t recommend this trick — but it’s worked for years. If Microsoft didn’t want users doing this, they’d have disabled access to the files long ago. This won’t help you pirate Windows 7, anyway — even if you download Windows 7 and install it on your PC, you can’t use it for more than 30 days without entering a genuine product key.
Update! Microsoft has removed the Windows 7 downloads from Digital River, but you can download them directly from Microsoft as long as you have a valid product key.
Some people report that the Digital River links sometimes go down, but they usually seem functional. Try again later if they don’t work. We’re linking to the English “Windows 7 SP1 Media Refresh” ISO files here. These are Windows 7 installation discs with Service Pack 1 and additional updates built-in. The x86 files are 32-bit versions, while the x64 files are 64-bit versions: Windows 7 Home Premium x86 SP1 Windows 7 Home Premium x64 SP1 Windows 7 Professional x86 SP1 Windows 7 Professional x64 SP1 Windows 7 Ultimate x86 SP1 Windows 7 Ultimate x64 SP1
After downloading one of the ISO files, right-click it in Windows Explorer and select Burn disc image to burn it to a disc. To install Windows 7 from a USB drive, use the Windows 7 USB/DVD Download Tool to put that ISO file onto a USB drive.
If you’re looking for the Enterprise edition of Windows 7, you can download a 90-day free trial of Windows 7 Enterprise from Microsoft and activate it using an Enterprise product key.
For links to Windows 7 ISO files in non-English languages and more information, visit HeiDoc.net.
If you want to just download the installation media for a fresh reinstall of Windows 8.1, there’s a new option from Microsoft that can allow you to download that image without even entering your product key.
And if you are completely reinstalling a Windows 8.0 PC you can use this 8.1 installation media with the same key from Windows 8.0, so there’s no reason not to do so. It even comes with Update 1 integrated.
Simply download the Windows Installation Media Creation Tool, and then select the details about which version you want (Windows 8.1 or 8.1 Pro, etc), and then follow through the wizard to create your boot media.
You can choose to put the boot media directly on a USB drive, or you can create an ISO for later use or to burn to a disc later.
It’s as easy as that.
Windows 8 and 8.1(Alternate)
Note: if you want Windows 8.1 media you should use the method above. Otherwise if you need to create a 8.0 boot disk for repair purposes, this is a good option.
You may still need to perform a fresh reinstall of Windows 8 or 8.1 on a new PC to get rid of all that bloatware. Computer manufacturers can bake their bloatware into the refresh image so the Refresh and Reset options won’t eliminate it.
Here’s the most important thing you need to know: Windows 8 and Windows 8.1 have different product keys. That is, if you have a Windows 8 license and attempt to install Windows 8.1 with your Windows 8 product key, you’ll receive an “invalid product key” message. You must instead install Windows 8, provide your Windows 8 product key, and then update to Windows 8.1 from within Windows 8. Yes, the Windows 8.1 upgrade is free if you’re using Windows 8, so this is just unnecessary pain.
Likewise, if you have a Windows 8.1 license, your Windows 8.1 key won’t work with a Windows 8 disc. You’ll need Windows 8.1 installation media to use a Windows 8.1 product key.
First, visit the Upgrade Windows with only a product key page on Microsoft’s website. Click the Install Windows 8.1 button if you have a Windows 8.1 product key or click Install Windows 8 if you have a Windows 8 product key.
Open the downloaded .exe file and enter your Windows 8 or 8.1 product key. This tool will create installation media that matches your product key — so, if you have a Windows 8 Professional key, you’ll get Windows 8 Professional installation media. The tool will create 32-bit installation media on 32-bit PCs and 64-bit media on 64-bit PCs.
Select Install by creating media and you’ll be able to choose between a USB flash drive or ISO file. The wizard will create a bootable USB drive or provide you with an ISO file you can burn to disc by right-clicking it and selecting the Burn disc image option.
If you’re looking for Windows 8.1 Enterprise installation media, you can download a 90-day free trial of Windows 8.1 Enterprise. Enter a legitimate product key to turn the trial version into a full, official version.
Microsoft provides other software via the TechNet Evaluation Center. For example, you could download a trial version of Windows Server 2012 R2 and enter a legitimate product key to get the full version. Older versions of Windows are found in the Previous Versions section of the TechNet Evaluation Center.
Image Credit: bfishadow on Flickr