Temps=Temperature i.e. what temperature is your CPU and system running at? if you can touch the heatsink on the cpu and hold it there for a few seconds it's fine. Shouldn't have too much of a heat problem with a 750mhz though, so that's probably not anything to worry about.
What brand/model is your motherboard?
Make sure you have the latest drivers for your motherboard and chipset!!
Just a thought, but why don't you try taking all but one stick of RAM out and then try it, if you still get the same results, swap it for another stick of RAM and try again.
Or, better yet, go
HERE and download MemTest86 and check you system memory. I don't know why but something tells me it could be the RAM. It's worth a shot...
HTH,
David
EDIT: Pardon my lack of alertness, and...
Welcome to TechIMO!!