Dying motherboard?

In the past 3 weeks I've had my computer give up on me 3 times.  The first time it wouldn't go past the loading screen, and after a restore of my system partition, it wouldn't even load in safe mode, saying that my system file was missing or corrupt.  Fresh install of Professional XP (I was using Home before), and it works fine again for a couple weeks.

Three days ago, it's doing the same thing.  I turn it on, and it won't go past the loading screen, the bar just stops moving.  I'm able to get onto it in safe mode, but not normally.  I turn it off, and leave it alone for the night, and in the morning, it starts up just fine.

Now, last night, while I was listening to music on here (logged in normally), the music started that high-pitched really fast skipping (only way I can describe it, really), and nothing would respond.  The sound gets quieter, eventually just stopping.  So I cut the power, start it up again, and I can only get to safe mode again.

The dying motherboard was a suggestion given to me buy a friend, but I don't know if that's the cause or not.  Any suggestions?

Also, this is a laptop, and one of the things I notice whenever this happens is that the memory stick indicator lights up.

Could be a heat problem. When my laptop used to overheat it exhibited strange symptoms, such as the mouse going bananas for a few seconds, before the system shut itself down. Is it doing this after being on for a while, or does it not boot from cold? First thing I'd try is dismantling it and cleaning out the inevitable dustbunnies that gather inside the fan enclosures, and applying a new layer of thermal paste to the cpu/heatsink (cleaning the old gunk off first, of course).

//Is it doing this after being on for a while, or does it not boot from cold?

When it initially killed itself, it had been on for probably 4-6 hours (happened while I was asleep).  Second time, probably the same, and last night, about an hour and a half.  This is my main computer, and normally it's on anywhere from 5 minutes to 1 week.

After it dies, it won't properly boot for about 12 hours.  Just boots to safe mode properly.

Check for dust bunnies

>>4
DUST BUNNINES KILLED MY FAMIRY!