Can i back up my registry by just burning it on a CD? How would i re-install the backup after i format? Do I finding the new registry - drag and drop the back-up over it to replace?  Wouldn't  I carry over registry problems also? I thought alot of PC problems are in the registry. It's those darn game keys I dont want to lose. Of course I'm assuming they are in the registry.

Take a look at this Microsoft article.
http://support.microsoft.com/kb/322756
Any existing problems with your computer will be carried along with the registry backup, so try to back it up when the computer is operating well.
All game keys should be in the registry.

   There is no reason to back up the registry to a CD.  You can just back it up to the harddrive.  If Windows crashes, the backup will still be on the harddrive.
   The only case when a backup on the harddrive would not work is if the hard drive crashed in which case a registry backup on the CD would be of no use either because you would have to restore much more than just the registry.
   If Windows crashes to the extent that it will not start, you will need a way to restore the backup outside of Windows.  We have a program which will make a boot CD for Windows XP to do that.  It is called XP Recovery CD Maker at http://xp-recovery-cd.com.  For Windows 9x, ME, our program, WinRescue, makes a boot diskette.  WinRescue is at http://superwin.com/rescuemenu.htm.
   With newer versions of Windows, a complete Windows crash where Windows will not start is rare but registry backups are still important to recover from times that Windows or installed software get messed up.  Our program, WinRescue, makes registry backups.
   No, you cannot backup and restore the registry in Windows XP or Vista, just by copying the registry files.  The registry files cannot be copied.  You will need a backup program to do that.