Possibly dead laptop, dont know where to start.
 

Seriously fed up. brought an old laptop on ebay a few weeks ago. Was fine, then I started getting BSOD's. microsoft.com hinted towards hardware failure.

I installed linux. Wanted to get back to the OS for a long time. It's been rock stable when compared to the amount of time windows was crashing. Every now and then it will lock up, or I'll shut it, come back to it, and It wont be on anymore.

When I turn it off after a crash, it will occasionally hang in fsck, occasionally it will hang while posting.

I really dont know where to start with laptops. Can I run a memory check, or could it be the hard drive? I really dont know. Any help is much appreciated.

I'd check the hard drive first. Determine the hard drive manufacturer and then download the hard drive diagnostics from their website. It's usually in the form of a bootable iso or floppy.

You can run a memory check on a laptop, no different than a regular desktop. I'd suggest just booting up Knoppix, then running the memtest from it. Instability usually is due to hard drive or RAM issues, or overheating. Good luck with it

It seems to be a physical problem after all. I think a connection is loose. I can shake the laptop, then keep it still, and it's stable for hours. If I accidently nudge it, it can freeze though, or not get past post if I try and boot. If this happens while posting, I get 3 beeps.

What sort of connection could this be? I've never opened a laptop before, I dont want to just tare it apart and randomly look for things that look disconnected.

Does this even seem a worthy theory?

Your theory sounds plausible. What make/model of laptop do you have? Also, could it be that your battery or power plug is loose - sporadic power glitches could definitely cause a lock up

Yeah, that definitely sounds like a loose connection somewhere. First thing I'd check (after what the previous poster suggested) might be the RAM - that's usually alot easier to get to on a laptop than opening the whole case up. If the RAM checks out ok, then an HD cable might have worked itself a little loose - you might want to see if the manufacturer has any "exploded" diagrams on their site of the innards of your machine, so at least when you open it up you have some idea of what cable goes where. If you do open it up, take your time - it's not all that different than opening up a desktop, but everything's packed in tight and there's usually NO play at all in the cables.

Good Luck!