random rebootings

Okay, so over the last. . . couple of months I guess. Maybe a little longer. My computer has been doing the 'yay screen sorta goes black and has some blue and other noise at the side and then suddenly it's all black and it's restarting' thing.

It's pretty predictable about when it does this (well, as in it'll repeat the thing when I do the same things). At first I thought it was just the GIMP disagreeing, as I installed it and ran it and it rebooted. About three times in a row. But it's done it at other times. Like today when I was trying to defrag.

I've checked the temperature, since I seemed to have made the silly mistake of taking the heat sink off of the motherboard when cleaning it, (it was hovering around 51 earlier, and it still is now, but it hasn't done the reboot thing), and it doesn't seem to be that. I ran window's little error checker on C:\, thinking it might be a bad sector or something? Since it tended to happen with the same programs in the same ways, and it didn't say anything when it finished, which was sort of unnerving, and useless. and on stu's suggestion, I ran this memcheck-86 thing, and it didn't find any errors either.

So now what?

How are you checking the cpu temps? Programs like speedfan and asus probe are notorious for reporting faulty temps, well below the actual core temps. Check through your BIOS, and if possible place a thermal probe next to the core.

When you touch your heatsink does it feel warm/hot? At 51C it should feel warm, if not hot to the touch. Make sure that the heatsink is making contact with the core and that a thin film of thermal paste or thermal tape is placed between the core and heatsink. It's good to reapply thermal paste (Artic Silver 5) every once in a while to make sure you're getting optimal heat dispersion. If the temp is actually 51C idle, while within spec, many new procs shutdown or slowdown at around 65C to prevent damage to the core. Are these random reboots happening when you're utilizing the cpu intentively? Do you get a looping sound when you crash?

If you're certain it's not anything concerning the temps, have you scanned for the usual viruses/spyware? Have you reformatted in this time? If so, did the problem only seem to pop up when you started installing programs/updates?

I have tried to find out how to check them through the bios, but I have no clue how to do that. There's nothing during startup that hints at the existence of it, etc. I remember years ago my brother said something about it apparently not using a BIOS. It's an hp pavilion 7955 though. I was using motherboard monitor 5 to check the temperature.

I would touch my heatsink, but it has a fan on top of it:( and another fan with a casing over it in front of it. I managed to get my fingers back there, and it didn't feel very warm at all. hardly any warmer than the air in the case.

I'm not sure that it's during intense CPU usage. I mean, loading GIMP shouldn't be more strenuous than executing commands on large files in PSP or Photoshop, should it? I dont' remember it making any sounds at all.

I haven't checked for viruses any more often than I usually do (being not at all) but I also haven't noticed any weird out of place processes or startup entries. I guess it wouldn't hurt to scan.

Check the power supply voltage rails and ensure that they are stable and within safe operating limits, especially when the computer is under heavy load. An unstable power source can cause the computer to freeze or restart at points of instability.

I'd also disable Windows automatically rebooting on bluescreening if that's what's happening, to see if there's any useful information there :p Right-click My Computer > Properties > Advanced > Startup and Recovery Settings > untick Automatically restart :p

Munty, that was the very first thing I did, on Jason's advice. It's never showed me any blue screens though :(

Also, sam, I do not understand a word of your post:D

Make sure there's only about a 5% fluctuation on your 3.3V, 5V and 12V rails. Again, this should be in the bios, but something like speedfan should be able to report that acurately. If you're seeing changes, especially on your 12V rail, below 11V or above 13V then it could be an issue with your power supply.

Do you have a GPU? I was having hardlocks whenever using graphic intensive programs until I bought a better cooler (Zalman VF700-U). You can't expect a company like HP to care much about their cooling solutions.

Speedfan doesn't seem to be too accurate. Under -12V it lists 68.28V xD Although I guess that would explain things :p

motherboard monitor won't display anything besides 3.3V and that seems to be at about 2.87?
a
sdgl;ds

I closed out of speedfan and it turned my fans off -.-

2.87V is somewhat low for a 3.3V rail.

I was looking around and found a folder of minidumps that all had dates corresponding to the times when I remembered my computer rebooting like this (three files all from the same day in february, when I couldnt' figure out why gimp kept making me reboot, up to one today)

Apparently they aren't supposed to be opened in notepad, but I did see kmixer.sys mentioned several times. I went to the system event viewer and found the logs for them, which were only labelled as information >:[ I would say this is more of an error than my mom's computer trying to become the master browser or whatever.

Anyways, here's what they said

Event Type: Information
Event Source: Save Dump
Event Category: None
Event ID: 1001
Date: 7/31/2006
Time: 5:10:19 PM
User: N/A
Computer: DIE
Description:
The computer has rebooted from a bugcheck. The bugcheck was: 0x0000009c (0x00000000, 0x8053f0f0, 0xa2000000, 0x84010400). A dump was saved in: C:\WINDOWS\Minidump\Mini[date]-01.dmp.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

stu thinks it's something to do with my PSU and voltages, but i'm just generally lost. Apparently the only other person on the entire internet with this error is german though :p

for the record, it has not rebooted in this way since, nor have I tried to run the gimp since. (aisle's thread made me remember. So it's clearly not a heating problem or voltage or anything else weird. )