Laptop freezes while hard disk acess is active

I use Win XP home Ed. on my laptop 512 MB memory. My laptop hangs in the
middle of a hard disk
activity. The hard disk LED indicator goes blank suddenly. And nothing
works. Same would happen when I tried rebooting. attempts at
rebooting fails repeatedly until I wait for at least an hour. And even then
after loading windows, it freezes . I used the SAFE MODE to load windows,
and the problem repeats itself there too. It just freezes. No hard drive
activity. during a hang up the following message appeared on a blue
screen:

"YOUR SYSTEM HAS A DETECTED A PROBLEM . IT STOPPED TO PREVENT DAMAGE TO
YOUR COMPUTER. THE PROBLEM SEEMS TO BE CAUSED BY THE FOLLOWING FILES.
WIN32K.SYS.
PAGE_FAULT_IN_NONPAGED_AREA.

IF PROBLEMS CONTINUE, DISABLE OR REMOVE NEWLY INSTALLED HARDWARE OR
SOFTWARE. DISABLE BIOS MEMORY OPTIONS SUCH AS CACHING OR SHADOWING. "

I have uninstalled every software I recently loaded. The probs still
continued.
The freezing problem was solved when I removed one of the 256 MB memory
modules.The system worked well. But when I install the module, its back to
freezing. I need to have 512MB working on my system. I need help please.

Clement

Laptop freezes while hard disk acess is active