Jesus, that has to be the neatest, clearest and most informed question ive seen so far..
OK, first off i dont understand why u needed the Windows XP CD inorder to restore the system to a state that it was in before.
The system creates restore points in itself every day and when u install new programs. The restore point on ur CD must be like old drivers - it makes the system go nuts. Plus u would lose everything that u have done..
So what i want u to do, it get to XP somehow and do a system restore by going to Start > All Programs > Accesories > System Tools > System Restore. Now restore to a few days ago or before the problems started to occur.
Also, go into the settings menu after the BIOS screen by pressing DEL. Check the temps of whatever u can find.
OR, download "Everest" or "System Analyzer" and check for temps and fan speeds.
Your system is very old, wich makes me assume u dont game. But just because ur not buying a new PC dosent mean that u should neglect to maintain the current one, and if u dont intend on buying a new PC anytime soon then u have even more reason to check out if there is a problem with a piece of hardware.
Its possible that the fans, being so old are not working well.