Random Restarting

I bought my new PC last December. Since that day I have been experiencing random restarts. I handed my PC to the shop from where I bought it. They replaced my RAM. After a week I started experiencing random restarts again! I handed my PC to the shop from where I bought it for the second time. They replaced My P5QC to a new motherboard: P5P43TD. After a week I I started experiencing random restarts again! I handed my PC to the shop from where I bought it for the third time!! Unluckily they said "We ran stress tests for days... and nothing seems to be wrong!"

Now my PC is randomly restarting again.
Sometimes it restarts after a week and sometimes aftar minutes :/
I thought it was my keyboard and I changed it. After changing my keyboard it took 2 weeks till the next restart... but then my PC started to restart again!!
I don't know what to do.

Help pls!

PS: Specs in my profile

EDIT: I forgot to mention that after restarting, I lose the saved passwords in the internet explorer. for instance: I have to re log in in Facebook.

Why there is no reply? do i have to be s gold member or something?

how can I do that pls?

ryo said:

lol...you just make sure that your hardware casing fan is locked..

open casing cpu. and look at your socket processor at the casing of fan processor..make sure that's locked all.

Yes it is locked...

DocBrown said:

seangalea said:

Why there is no reply? do i have to be s gold member or something?

Have you checked Event Viewer to see what some of the events were that happened ?

I don't even know how to access that

ryo said:

• Open Event Viewer by clicking the Start button , clicking Control Panel, clicking System and Maintenance, clicking Administrative Tools, and then double-clicking Event Viewer.* If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

Ok... I accessed that. What do I do now?

EDIT: Im not sure if I found the event I was looking for. If yes, the source seems to be Kernel-Power...