Just upgraded windows 7 to SP1 and now CPU usage 100%?

[DjAnnexAlpha]

Just upgraded windows 7 to SP1 and now my CPU is running on 100%. But before that I could not log on into my Admin account (main account I use), so I researched online how to solve this, and it forced me to change some files from BAK to BK then BK to BAK then delete the BK. Then, I upgraded windows 7 to SP1 and everything got worse. Please help.

 

[Mark56]

Use this guide to track down the problem.

http://windows.microsoft.com/en-US/windows7/Run-Selective-Startup-using-System-Configuration