Windows 8 OEM machines no longer include a COA sticker or label at the bottom of your laptop with your serial number. If you need to re-install your Windows and your hard drive's recovery cannot be accessed or you forget to create recovery discs - it's a difficult process.
Here are the reasons people want to clean install Windows 8.1:
Some people believe a clean install is better than an upgrade from Windows 8
People forget to do a recovery disc backup and their hard drive's recovery doesn't work. This could be for a variety of reasons (mine was a new SSD installation, while others have reported wiping their drives or recovery partitions becoming inactive or corrupt)
Guaranteed removal of bloatware—even if you did obtain recovery discs, people don't like all the added on applications that OEMs supply with their machines.
Saving the $$$ involved in obtaining recovery discs from the manufacturer (such as Toshiba who thought it was ok to charge me $68 US to ship me recovery discs—with bloatware)
Here is the process
First, find yourself a retail copy of Windows 8.1 ISO. Get the version that corresponds with what came with your laptop (e.g. Professional 64bit). You can download from My Digital Life forums or even find one as a torrent or download directly from Microsoft if you happen to also have a valid retail serial number or dev account. I recommend to check the MD5 hash to make sure the files are original if downloading from torrents. (Remember, downloading a Microsoft ISO is NOT illegal as long as you are installing it with a legal license)
Next, install the ISO by burning it to a DVD and booting from the DVD. You may have to change your BIOS settings to allow booting from DVD as the first boot device.
Install Windows 8.1 Retail with a generic key. Microsoft has now released LEGAL generic keys used for the sole purpose of installing Windows 8.1 as an INACTIVATED copy.
Generic keys can be found by simply googling:
windows 8.1 [version] [32 or 64 bit] generic key
Finally, once the Windows installation finishes, open up an elevated command prompt. To do this right click on the Windows button and click Command Prompt (Admin).
In the window type:
This will uninstall the product key (which is generic and inactivated anyway).
Once this is done, use a program like RW Everything
to extract the key that is embedded in the bios of your OEM machine or .
Once you open it, click on the ACPI button then click the MSDM tab. Your
key will appear at the end of the data window as the value for the key
"Data". Or, use
If you want to get the product key, you can extract it by using Belarc Advisor.
Open an elevated command prompt again and type:
This will open up a GUI request for your product key. Paste the key from RW Everything.
That's it, you're all done.
You will notice you are fully activated and all of your Windows updates will work.
I have also made a simple tutorial video that explains how to do it all for those that want a more visual demonstration.