I've been having some trouble with my computer for a long long time!
I have a Lenovo 3000 N200, with a 100 GB Hard-disk. I've always had trouble with it. At the start I had vista installed. At some point windows wouldn't boot anymore. I thought that vista was the cause of it, so I found a XP version to use. But that also caused me trouble. At some point windows simply stops working, so I have to format my computer around every 3 months or so - which is a real pain!
At one of those formats, I decided to split my HDD in two partitions, so I didn't have to make backups of all my work. After that I've experienced fewer crashes.
I've also noticed that when my second partition gets filled up so there is only around 10 GB left, windows crashes (while I'm copying the file over). If I delete that new file again, there's no problem.
So after years of trouble, I'm finally pretty sure of what the problem is. I just have no clue if it can be fixed.
So if you have any ideas of how to fix this, please let me know! (There's no warranty on it anymore - had it for almost 4 years)
Additional info: At some point if I tried to defragment it, it would also crash.