I've been havin this problem for weeks now.. i sent it to the service center but after a few days, the comp restarts unexpectedly again.

my specs
-p4 3.0 ghz
-gigabyte f8s648fxp-rz motherboard
-1gb ram
-sony dvd rom
-sony rewritable cd rom
-128 mb geforce fx 5200

wat more info should i give u and how?
please help..
thx

Hello and welcome to Techspot.

What did the service centre say the problem was?

Go HERE and follow the instructions.

If that doesn`t help. Zip 5 or 6 minidumps together, and attach them here.

Regards Howard

Hmmm.

Does the pc sometimes restart whilst still loading Windows from the previous restart? Suddenly restart once the PC has finnished loading the Desktop?

Well I had those two symptoms above whilst my Power Supply was dying. I could hear a clicking sound usually just before the restart. Took the pc to a pc fix-up place and they confirmed that is was the power supply an then they replaced it. Since then the restart issues have been gone.

Either try using someone else's Power Supply and see if the restarts are still there. If they are not then the power supply was the problem.

Or take you pc to a pc fix-up place and let them have a look at it.