Regedit I did it again?

First I like to thank all of you for your advice on how to over ride my hard drive.
Now my new problem.

I was trying to update my drivers for my CD/DVD.

After following the simple instructions of going into the regedit and the hkey and removing one of the reg keys I lose my mouse and keyboard drivers.

I back it up in my document folder.

It was suppose to put them back after restarting.

Well it didn’t.

I can get the keybroard to work in dos/safe mode but just can’t get the drivers to come back on.

Can I put the windows disk in, start my PC from there without loseing anything?

Yes this is the same PC with winXP on it.

Thanks for your help in advance.
frogwillie2001@yahoo.com