Long install/loading times after Core 2 Duo/mobo(nForce 750i SLI) upgrade

First off, this is my first time posting on these boards. If this is the wrong location for this please move this.

My rig:
win xp sp 3
intel core 2 duo 3 ghz (part upgraded)
Crucial 2 gb 420 ddr2 ram
nForce 750i sli mobo (part upgraded)
750 W PSU

After changing out the mobo and cpu, sorry I'm unsure exactly what it was before, install and loading times for games are a lot slower then they where before. We are talking 10 min install times becoming 3 hour waits. This is not just limited to only one program/game.
The programs do install properly after they install and games run fine after the long load times.
At first I believed it was because I run everything on my external hard drive, but that is not the case. I tried running stuff on the internal one and the problem was the same.

What I have done so far:
Updated all drivers.
Checked to see if all previous hardware is compatible.
Checked to see if cores are working properly.
Loaded "optimized settings" in bios.

Any suggestions would be greatly appreciated.