Also see these MS TID's:
http://support.microsoft.com/directory/article.asp?ID=KB;EN-US;Q183169

http://support.microsoft.com/directory/article.asp?ID=KB;EN-US;Q192463

http://www.win2000mag.com/Articles/Index.cfm?ArticleID=16425

0x00000050 errors are usually a result of a bad driver so run sigverif to check for unsigned drivers.  Could also be RAM/Hardware related too...


start  |  run   and type  sigverif.exe
Advanced tab and  click 'Look for other files that are not digitally signed {Winnt\System32\}

1) Get the latest drivers for ALL of your hardware.

2) Get the Latest BIOS update

3) Check the hardware, especially fans, overheating etc.

4) Run a full hardware diag on this machine. Norton etc.

It could also be a motherboard defect causing this.

 I hope this helps !

sheesh sysexpert that sounds soooo generic...

does it reboot at random times or when u start the computer, run a program, or open drives?

Reboots are usually hardware problems including defective cards and most often power supply problems.

 If you know the machine will reboot within a few days. Remove all non esential cards for a weekend. Sound cards and Networking cards and run your machine in safe mode to reduce the driver interaction with your Video card.

 If it still reboots it is probably the power supply.

 If it doesn't reboot it's one of the cards including the video card / drivers. Put in one card and run in normal mode for a few days.

 If it reboots it's the video card / drivers or the inserted card. remove the card run again.

 You get the point eventually you will have narrowed your problem down to a card or upfront with the power supply.

 I don't suspect drivers because you didn't say you had this problem since installing XP, a new card, or patch.

Cheers

also check the inside of the computer to make sure nothing could possibly be causing a short circuit.  Possibly an electrical component that's slightly making contact with a screw on the motherboard or something.

It's probably rebooting automatically instead of displaying a Blue Screen of Death. Do what shekerra said and see if the problem is the BSOD.

there's one caviat to that whole driver update thing. I for one found that installing XP SP1 made my system reboot whenever I watched any movies on my dvd. Take it step by step. If you've already reinstalled the OS and have service pack 1 installed remove it. See what happens.
2. also as stated previously check the dumplogs and the event viewer for any errors . Some typical occurances of reboots include the following: An application instructing the OS to; Power Supply not supply enough power, and the video card. Verify that the latest drivers are up-to-date, make sure you don't have a powersupply taking a dive on you, and if possible see if you notice any cominalities when it reboots. Are there any applications that are running consistly when the reboots occur?

Best of luck
Tomm

I checked for unsigned files but there were a couple hundred or more so it was quite meaningless to me.
I will try running Norton System doctor to see if that will help.
I have unchecked the option for automatic reboots so I assume that will show whether it is software or hardware. If it is the BSOD then I will see that next time.

Below are the error codes for the dump file found in Event Viewer for the last 5 reboots.

The debugging and dump analyzing software is over my head and I just don't have the time to pursue that right now.
*************************
The computer has rebooted from a bugcheck.  The bugcheck was: 0x000000d1 (0x89683670, 0x00000002, 0x00000001, 0xf62f0e49). A dump was saved in: C:\WINDOWS\Minidump\Mini111102-01.dmp.

The computer has rebooted from a bugcheck.  The bugcheck was: 0x100000ea (0x81758a68, 0x815e0390, 0x8172b5e8, 0x00000001). A dump was saved in: C:\WINDOWS\Minidump\Mini111002-01.dmp.

The computer has rebooted from a bugcheck.  The bugcheck was: 0x00000050 (0xe0b3ff0f, 0x00000001, 0xbf832d50, 0x00000000). A dump was saved in: C:\WINDOWS\Minidump\Mini110902-01.dmp.

The computer has rebooted from a bugcheck.  The bugcheck was: 0x000000d1 (0x00040001, 0x00000002, 0x00000001, 0xf9d0c552). A dump was saved in: C:\WINDOWS\Minidump\Mini110702-01.dmp.

The computer has rebooted from a bugcheck.  The bugcheck was: 0x000000d1 (0xfa31f8ff, 0x00000002, 0x00000000, 0xfa31f8ff). A dump was saved in: C:\WINDOWS\Minidump\Mini110502-01.dmp.

The computer has rebooted from a bugcheck.  The bugcheck was: 0x000000d1 (0x00000060, 0x00000002, 0x00000000, 0xf9b2b844). A dump was saved in: C:\WINDOWS\Minidump\Mini102402-01.dmp.

The Event ID for all above is 1001

you'll need to go to the web and download a utility that will enable you to read .dmp files Microsoft has them. this will help translate the issue and bring it more to light for you. Let me know what is finds out.

How to Gather Information After a Memory Dump in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q314084

Download Pstat here
Pstat.exe: Process and Thread Status
http://www.microsoft.com/windows2000/techinfo/reskit/tools/existing/pstat-o.asp 

Thanks, I will download Pstat and try to wade through the dump file.
I find it amazing that Microsoft makes the OS that creates the dump file upon an error and they have a program you download to decipher the dump but they can't incorporate this "know how" into their OS so that an ordinary user could figure out what the problem is.
If Microsoft made cars they wouldn't have a "low oil warning light" they would have an error code that pops up on your dash that says:
"There is an error with your engine. The bugcheck was: 0x100000ea (0x81758a68, 0x815e0390, 0x8172b5e8, 0x00000001)."

In the Startup and recovery settings I unchecked the box for "automatically restart" however the computer had an automatic reboot yesterday nonetheless. Does this mean it is a hardware problem rather than a software problem? The stop error codes are different everytime it occurs.

See my previous post for info on what I would suggest to get your problem resolved.

 I hope this helps !

Also see here:
...D1 dump:
http://support.microsoft.com/?scid=kb;en-us;q316208
...ea dump:
http://support.microsoft.com/?scid=kb;en-us;q293078
...50 dump:
http://support.microsoft.com/?scid=kb;en-us;q310628

I still have not resolved the problem but Shekerra's comment was the most helpful. Thanks to everyone who made suggestions.