Yes, there is a way. A program available (for free) from PC Magazine, called 'Registry Robot'.
It allows you to change numerous registry settings, and it also has a section which will tell you the CD Key of the Windows your computer is running. (Under the System/Information/Retrieve a lost CD-ROM Key).
It's a handly little program in it's own right. It contains numerous registry tweaks which it can done one by one, and can also be undone, with just a click of the mouse, such as: Changing your icon cache, removing icons from the desktop, changing the logon screensaver, changing the icons used for drives, renaming the recycle bin, and changing the location of special folders, just to name a few.