Good-oh. Kristy, but do that system state backup only after you are clean! [otherwise your reg backup may contain some dud entries..]
Do those cleanup steps first, in the order I wrote them.
Actually, you can just get those 2 files from your install cd. This is from M$:
1. Insert the CD into the CD drive or DVD drive.
2. Click Start, and then click Run.
3. In the Open box, type cmd, and then click OK.
4. At the command prompt, type the following commands, pressing ENTER after each command:
expand CD-ROM Drive Letter:\i386\config.nt_ c:\windows\system32\config.nt
expand CD-ROM Drive Letter:\i386\autoexec.nt_ c:\windows\system32\autoexec.nt
Simple! The full article is here:
http://support.microsoft.com/kb/324767