Are we talking about a Microsoft OEM version, or a Dell/Gateway/HP/Toshiba/Sony recovery disc.
You have no chance of fixing this easily, because the product ID for one will not work on the other.
If OEM, talk to Microsoft which will send you a new disc for a price, then you can use your existing Product ID. If you have one of the proprietary recovery discs, you can almost always buy a new disc set for less than $27 including Fed Ex shipping. Dell will send you a new one if the computer is still under warranty or was under warranty in the past year... and they charge you nothing.
