"recovered from a serious error", computer rebooting randomly.. HELP!!

My Windows XP computer keeps getting a "System has recovered from a serious error" message on every restart. At first, nothing else seemed wrong so I just ignored the problem, but when I turned it on today, it kept restarting and restarting over and over again, and would also randomly start rebooting while in use. I opened the case, and replaced the RAM cards, dusted the case thoroughly (dust had been a big problem once), and plugged it back in, but the problem is still there.

(When I send the error report to microsoft, it says that the data in the error report is corrupted, so that's no help.)

Could someone please have a look at my minidump files and tell me whats wrong? I'm completely lost, and don't know where to begin to start identifying the problem. HELP!

3 of your minidumps are corrupt, and unreadable.

2 minidumps crash at atapi.sys. This is your Windows IDE/Atapi port driver. Both minidumps have a bugcheck of D1.

0x000000D1: DRIVER_IRQL_NOT_LESS_OR_EQUAL

The system attempted to access pageable memory using a kernel process IRQL that was too high. The most typical cause is a bad device driver (one that uses improper addresses). It can also be caused by caused by faulty or mismatched RAM, or a damaged pagefile.

It could be that this driver has become corrupt, or it may be a sign of a failing hard drive.

Go HERE (http://www.techspot.com/vb/topic35103.html) and follow the instructions for testing your ram, and running the hard drive diagnostics.

Also. If you scroll down the page. You will see instructions for creating a new page file. See reply #11.

If that doesn`t help. Maybe doing a Windows repair as per this thread HERE (http://www.techspot.com/vb/topic8356.html) might help.

Regards Howard :)