Hello all. For about the past 4 days, my computer has been randomly rebooting by itself. I am running WindowsXP SP3. I did a system restore to roll back my system to a date when everything was running fine. Unfortunately, this did not solve the problem.

Here are the relevant messages from Event viewer from the first system error event to the most recent (4 in total so far):

1)
Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 11/26/2009
Time: 3:26:24 PM
User: N/A
Computer: COMPUTER
Description:
Error code 0000004e, parameter1 00000099, parameter2 000fffff, parameter3 00000007, parameter4 00000000

2)
Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 11/28/2009
Time: 12:14:02 AM
User: N/A
Computer: COMPUTER
Description:
Error code 1000000a, parameter1 003c0070, parameter2 00000002, parameter3 00000001, parameter4 804ea16f

3)
Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 11/29/2009
Time: 2:48:48 AM
User: N/A
Computer: COMPUTER
Description:
Error code 1000008e, parameter1 c0000005, parameter2 bd1f132a, parameter3 b25d287c, parameter4 00000000

4)
Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 11/29/2009
Time: 7:25:03 AM
User: N/A
Computer: COMPUTER
Description:
Error code 1000008e, parameter1 c0000005, parameter2 bd1f132a, parameter3 b518f87c, parameter4 00000000

I have also uploaded the most recent minidumps as a zip.

Thank you for any help you can offer. Much appreciated!

Try updating drivers and your BIOS. Have you recently made any hardware changes? From what I've looked up, it seems like it's definitely related to either a hardware change or bad RAM. The latter is easiest to test: remove all sticks and try one stick at a time.

Along with the random reboots, do you hear a strange clicking noise coming from inside the machine just before it reboots? Usually, the system temporarily freezes up completely while the clicking is occurring. If this is the case, then your HDD is dying on you. Had this happen to an old system of mine. The reboots were random, then started happening more frequently until the Windows spalsh screen was all you'd see before it rebooted again. If this is what you are experiencing, then stop using your computer until you get a new HDD, because this means there is a physical error on the surface of the disk, which is not repairable. Let's hope that it's just a bad stick of RAM.