my computer is
asus a8n32sli deluxe mobo
2 gigs of memory
one sata 2 hdd
one 8800 gtx
fx60 dual core processor
and i forgot the make of the power supply but it is 550 watt
i ran memtest while windows was running since my computer wont boot off of a cd even if i change the load order in bios.
My computer is very similar to yours. That ASUS board can be very picky about ram. Worse, if its one of the early boards, it can underpower some types of ram and cause errors. I don't know the brand and specs of your ram, but you might try bumping up its voltage in the BIOS. I had to do that on mine to stop the errors.
You should open the computer and check on the make and specs of the psu. If its an old one, or one of dubious quality, it may be giving out as well. If it starts to fail and doesn't give sufficient power to the motherboard, you can also get ram errors. I had to replace my psu because of this, though it didn't fix all the problems.
Last, if you have a floppy drive, install memtest on that and try it. I couldn't get memtest to work on my computer when using a CD, but it worked fine from a floppy. Don't know why, but that's what happened.