Laptop freezing frequently

[Firus]

Over the past two days, my laptop has been giving me trouble. I'll start it up, it boots normally, and then I do whatever for about 5-10 minutes, at which point it freezes (mouse still moves but nothing reacts, clock stops moving, sometimes mouse eventually stops moving too). At first, Ctrl Alt Delete did nothing, but now it brings up a full black screen (as if trying to produce the options screen) and then, after a few minutes, gives me an error, saying that it failed to load the Security Options. From what I can tell, no program is causing this; it seems to simply happen after a certain amount of time. The only changes I've made recently are uninstalling 2 games that were taking up space and installing my capture card software.

I've since, however, made a system restore back to Christmas Day (reinstalling the games) and the problem does not seem affected. I've also run multiple virus scans and found no problems.

For background, I'm running 32-bit Vista, and my laptop is a Dell Vostro 1510, if that changes anything.

Does anyone have any ideas of what the problem might be and/or what I could do to solve it? As a last resort, I do have my files backed up on my external hard drive (Christmas Day was the last time I did a backup) so F-disking it is a possibility, but again, that's an absolute last resort.

(I've written this from my iPod Touch, so I apologize if there are any typos I've missed.)

 

[Gerudo Warrior]

Im a mac/linux user here, so my advice might not be accurate. I would try doing a file system check (fsk)

 

[Diddyknight]

Try to Defragment the hard drive. Scanning was the right thing to do at least for instinct. My computer did the same till i changed OS >.>

*defragment
*check registry

Try those 2 options for now

 

[Firus]

Oh yeah, I forgot to mention that I did a disk check, too. I'll give defragmenting a shot too, though; thanks.

EDIT:

Well, I gave defragmenting a shot and nothing happened...but then I was talking to my friend, who mentioned that his old computer ended up dying due to a problem similar to mine, because so much dust got in his computer and stopped his fan from working. After he mentioned that, I realized that my usually quite noisy fan hadn't been doing anything since the problem started up. Since the fan would cause the laptop to overheat, therefore causing it to freeze after a short amount of time, this seems pretty plausible.

So at this point I need to get the fan replaced, though I'm not sure how soon that's going to happen.