Hi Jay.

I was having this exact problem after installing V6. It seemed to happen at random, usually a couple of hours AFTER doing some editing on Vegas... I could be on the IE, Word, or any other application. Tried everything, new drivers, bios, re-installed xp (still recovering from that), and finally replaced all system RAM (all 2 gigs).

Since I did that, NO more problems -- See:



-Travis

It could be caused by lots of thing unfortunately. The first thing I would do is go to Control Panel > System > Advanced tab. Under Startup and Recovery press the Settings button. Under System Failure, uncheck Automatically restart.

This will give you the Blue Screen of Death (BSOD) which will at least tell you what failed. You can then look up the error and have a clue as to what is going on. I had this problem once and it was caused by a driver that never uninstalled when I removed some hardware. I finally formatted my PC to get rid of it.

This can also be caused by a failing memory module or a failing power supply (or just an overstressed power supply if you’ve just added a bigger hard drive or something that draws more power)

Of course in the summer, heat can also be an issue. Vacuum out the PC case and especially around the CPU fan where dust tends to get packed in because the fan blows down on the heat sink fins. Good luck, I hate debugging those types of problems.

~jr

vaccuum may not be a good idea because it can generate static electricity and kill things that way.

Canned air will work and I believe people say it's safe (at least safer than vaccuum).

2- Definitely uncheck Automatically restart as JohnnyRoy suggested.
If you aren't getting BSODs, it's likely a hardware failure of some sort.

If it's hardware...
Run prime95's torture test along with a temperature/voltage monitoring utility.
Prime95: http://www.mersenne.org/freesoft.htm
Monitoring: Motherboard Monitor, Speedfan. The best is your mobo manufacturer's tool... it is the easiest to configure.

If CPU temp is too high, READ the instructions for installing the CPU. Re-install it. Read the instructions, otherwise you can damage things.
Power supply failure will show up as low voltage when you are running the torture test.
Prime95 errors indicates CPU overheating or RAM failures. If CPU is not overheating, it's likely the RAM. Try each stick, and try a known-good stick.
Motherboards can also be the problem sometimes. That situation sucks, because you have to elimiate everything else or just try replacing the motherboard (but windows may not boot if you don't prep your system by installing motherboard-specific hardware).

This is a shot in the dark but I've had spontanious reboot problems on 3 computers - each time putting in a new power supply solved the problem.

Never had a problem with Antec stuff.

good luck

Possibly bad RAM. (I have some "bad" RAM that only operates properly when overclocked. Wierd stuff, but it does cause spontaneous BSODs under normal conditions. And if your computer is set to automatically reboot on a BSOD, it matches the symptom.)

Get yourself a copy of memtest86 and run your computer through its paces. I found my problem immediately. Good luck.

My thanks to everyone! Now, I have to go down the list and try each suggestion and hope that one of them works, short of having to reformat my C: drive. I hate that the worst way in the world.

Yes, Travis, this all happened after I installed Vegas 6 (which has since been uninstalled).

Larry, no PACE protected software here.

[edit]
Went back and read your thread, Travis. Let me ask: What's the difference between a crash and a simple reboot? Like I said, at times I wasn't doing anything. The computer was sitting quietly, no apps open, just the desktop and all of a sudden it would reboot itself! Sometimes hours apart, once just 30 minutes between reboots.

I believe a crash means the machine is hung and will not reboot by itself. A reboot is something else.

JJK

I had what I would best describe as just general instability (instability, of course can mean anything, which is what I had.) Yes, several times, the computer simply rebooted, I wasn't doing anything with it, and the screen went dark - a few seconds later the bios startup messages appeared, exactly as though I had started the machine from power up. No error messages or anything.

Several times I got a message something like "Windows has recovered from a serious error....etc. etc." It would then attempt to diagnose the reason for the shut down. I got different diagnoses each time that happened, with Microsoft blaming drivers one time, memory the next, and my internet secuity system (i.e. Norton) the next.

Before I replaced the memory, I replaced the power supply (a good thing, actually, 'cause the new one is much quieter.), unplugged and replugged all the cables, updated all the drivers, swiched out the video card, checked the drives, used Microsoft's "memory test" program (only for a half-hour, during that time it reported everything ok), reformatted the OS C: drive and re-installed XP, disconnected various USB devices, none of which seemed to work. It is possible that some of these attempts AND the memory replacement together solved the problem.

Reformatting and re-installing XP is always a good thing to do, but it sure is a terrible thing to do.

Goood luck....

Travis

Had the exact same problem. Took my computer into a repair shop and it turned out the CPU fan was malfunctioning. Once the CPU overheated.... poof.... instant reboot.

Fortunately, I hadn't fried the CPU. My repair guy charged me $5 for a new fan and $10 for labor. Open the case and make sure the CPU fan is turning.

"I wasn't doing anything with it, and the screen went dark - a few seconds later the bios startup messages appeared, exactly as though I had started the machine from power up. No error messages or anything."

Exactly, Travis!

Brain, I'll give that a look.

Thanks!

Jay,

It may be that you have a protection mode built into the motherboard that reboots once you hit a certain temperature as a way of preventing too much heat from building and the CPU frying.

I'm pretty sure you can get fans that only kick in when your computer's temperature reaches a certain point, though I don't know if you need to change your board for that.

Jay:
Try running Prime95. It'll show if the problem is your CPU or not. On the first screen, do not join GIMPS because you are just testing.

If you can get Motherboard Monitor or an equivalent program running on your system, it is a good way to check for power supply problems. Run it in conjunction with Prime95's torture test.

I give up. It won't even let me reformat the hard drive. It gets 34% formatted then reboots! How can it reboot the hard drive if 34% of it has been reformatted?

I'm just going to go out and buy a new hard drive and be done with it. I don't know what's happened, but this stinks.

Ya know it could also be the motherboard, memory, power supply, fans, & processor.

JJK

What's up with the CPU fan?

Update: I tried reformatting using "Quick" format. It took two tries, but got through the process. Then, as I was installing my first program, it rebooted. <sigh>

Brian, the CPU fans is spinning its little butt off. Using canned air, I dusted the CPU heat sinks earlier this morning.

James, I don't know what's wrong or what to do, short of buying a new computer.

If you are going to build a new computer, you might start by just getting a new powersupply for this one. If you set Windows to show the BSOD and it’s rebooting without that screen showing, it could be the PSU failing (even bad memory should show the BSOD). A new $60 PSU is way cheaper than a new PC. If you are going to buy a new PC then a new PSU could be $60 wasted (since you won’t be using it in the new PC).

When I had this problem, I removed some old cards that I didn’t need and the reboots stopped. This proved to me that it was the PSU being overtaxed. Try removing all non-essential cards to reduce the load on the PSU. Maybe even disconnect an extra hard drive or two and run it for a day to see if it’s a power consumption problem. Of course if the PSU is failing (and not just overtaxed) it will still reboot randomly.

~jr

Have you tried pulling one of the memory sticks out, then the other to see if it is a memory problem?

JJK

Johnny, I don't have any non-essential cards in the system. When I built this system three years ago, I installed a larger power supply than necessary to avoid this very problem, if it is the power supply. Guess that's as good a place as any to start. Problem is I'm loosing time on a project I'd started (it's on another disk drive, so it's still there, thank goodness).

James, it only has one memory stick. Guess I could chuck it and buy two new ones--upgrade to 1GB.

Just out of curiousity what power supply are you using?

It's an Aspire 420ATX-12V. As I recall, it came with the case. It was the same case used by AlienWare when they first started, I forget the brand.

Update #2
I turned off the Automatic Restart on Error function and it still happens... no BSOD, though. I've ordered a new power supply and 1GB of RAM. I really hope one of those fixes the problem. From what I've read elsewhere, as some of you have suggested, it could be the mother board, heaven forbid! If that's the case, I may as well upgrade everything, right?