"Not all Windows XP CDs and Licenses are the born equal. There are many different types of Windows XP CDs available such as OEM, Retail, Upgrade, Branded, Action Pack and Volume License versions. The problem with different versions is the license key from one version typically wont work on another version. If you have a retail license key, it wont work on an OEM disk. So you cant just "borrow your friends" CD because you lost your own. So how can you find out which license key and CD you have? Heres how."