Any chances of fixing a broken mainboard?

"Update 3: The computer crashes
sometimes. Especially when starting
windows. It has successful passed a
memtest, but it crashes after some
time testing the hard disk for bad
blocks.

First, I'd recommend downloading the ultimate boot CD - it has a broad variety of diagnostics that could come in handy.

There is definitely a hardware problem, hence the knee-jerk ""mainboard"" diagnosis. As has been suggested, your best bet is to strip the system down as much as possible and test. Then add back one component at a time to see where it starts to fall down.

From what you've said so far, it sounds like either a problem with the HD controller (integrated in the mainboard) or a RAM problem. You might want to run a RAM test overnight to see if it turns up any problems."

"Most likely no. You'll need to have it replaced. If it shuts down, it's probably shot.

If the computer turns on, shows lights, stays on, but hangs, I'd say it could be fixed by resetting the bios/cmos. But shutting down immediately doesn't sound good. We'll need more info to possibly help."