new computer stability issue...

[Gamingfreak]

Hi, i recently built a new computer and at first i thought it was running fine but every now and then it would restart on its own. I started off by checking the bios and setting the voltages to their defaults except the chipset because i couldnt find out what the default was for that so i left it on auto. I ran prime95 and superpi to get my cpu up to 100% and i got an error after about 10mins. After playing around with the chipset voltage i realised that the only way its stable is if i run it at the highest voltage which doesnt seem normal to me at all.

Do you guys know what could be the problem?

Build: ASUS P5B deluxe, Intel E6600 cpu, Corsair XMS2 ddr2 800mhz, nvidia 6800gt gpu

 

[sPlAtOiD]

Are you sure the heat sync is seated snugly and did you use thermal paste. What are your temps. Also check your memory.

 

[Gamingfreak]

Im pretty sure the heatsync is on right and i did use thermal paste, my cpu at idle is about 38C and under load 48C. As for my memory i was going to check it with memtest but i dont have a floppy drive at the moment. Is there any other way to run it?