This is Windows 10 different versions on 8GB USB Drive. This USB drive DOES NOT includeMicrosoft windows Activation Key. You can upgrade your PC to OS 10 if you have previous OS and use your old key. However, not all PC can meet the minimum requirement for Windows 10 .Please check Microsoft to see if your PC is eligible or not. 

Please check the above instructions before you buy this Item. 

If you still has windows running and before you going to reinstall win10 and need to locate your Microsoft Activation key, pls do the following :Type in “cmd” and press the Ctrl + Shift + Enter keys on your keyboard. By doing so, you’re launching the Command Prompt with administrative permissions.
If prompted by the User Account Control (UAC), click Yes to allow the Command Prompt to make changes on your device. If you don’t have administrative permissions, you might need to ask for help from your admin.
Type in one of the following commands, then press the Enter key to execute them: 
wmic path softwarelicensingservice get OA3xOriginalProductKey 
or 
PowerShell "(Get-WmiObject -query ‘select * from SoftwareLicensingService’).OA3xOriginalProductKey"


Otherwise, your Widnows Activation key, should be located it at the back of your PC