I agree with above,well first of all I think dells are proprietized machines, meaning they give you a restore disk, in changing mainboard cpu, you have now changed there config files,,thus creating more problems, if your going to change mainboard & cpu,,I would suggest a new hard drive,, get os xp etc and do a clean install,,might save yourself some headaches..there restore disks are set up to there hardware specs,,need help doing anything let us know, we will help you.
Bd