PC randomly freezing

[CSmith]

I'm at my wit's end over an issue with my computer randomly freezing, so I was wondering if anyone here would possibly have any idea what's causing it.

I built this computer last June. The specs are:

Intel Core 2 Duo E8400

ASUS P5QC motherboard

4 gigs of Kingston KVR1333D3N9/2G RAM (2 sticks)

ASUS Xonar D2X sound card

GeForce 9500 GT video card

Windows XP Home

Up until around November, I didn't have one problem from the computer, but for the past several months I've been having freezing issues. I'll be listening to music, or browsing the web, or trying to talk to family on Skype and the computer just completely stops. There's no indication that it's going to happen, and nothing consistent about it at all.

Sometimes I can leave the computer running for over 24 hours with no problems whatsoever, and sometimes it will freeze within minutes of booting into Windows. And it can't be a problem with Windows because a few times it has frozen during POST.

Friday when I got home from work, I turned the computer on and had to reboot it from freezing 6 times in less than 30 minutes.

I've run tests on the memory, the CPU, and the hard drives and I have no idea what's wrong. I'm thinking maybe it's the power supply, because sometimes when I turn the computer back on after a freeze, the case LEDs and some of the fans come on (but not all of them) and the hard drives don't spin up. I checked again yesterday to make sure all cables are completely plugged in.

One thing I don't get though, maybe someone can explain this to me, is for example, if I'm watching a YouTube video or something when the computer freezes, of course the video stops, but when the computer froze while I was running memtest86+, the animated + sign was still flashing. Also when watching videos or listening to music, if the computer freezes, the last split second of whatever I was listening too loops over and over.

One last thing (not sure if any of this is actually helpful), when I turn the computer off after it freezes, by holding the power button down, the num lock light on my keyboard stays lit even though the power is off.

If anyone has any idea what's wrong with my computer, I would be grateful for some advice!

[prophetik music]

how big's your power supply? likely not anything to do with that, but it's worth checking.

freezes generally related to a crappy motherboard or bad ram. you have crappy ram, but if memtest is working fine then it's not that. you didn't list a great motherboard - it's usually stable, but nor much more than that.

the light thing makes me think your psu is just defective, incorrectly interpreting the power-on signal (the thing it uses to activate a UPS if it craps out).

[CSmith]

Oh, the power supply is a Corsair 750 watt.

Any way to check whether it's the motherboard or not?

[prophetik music]

that should be way more than enough power for that system, since the draw should only be around 250-275 watts (you could have gotten by with a 450w that was 80-plus certified ).

there aren't many ways to check if it's a motherboard or not.

do you have a spare hard drive sitting around? try disconnecting your HDDs on your system - all of them, if you have more than one - and installing some operating system onto it. see if it causes freakout errors still. that'll narrow it down to your hdd or motherboard. if your hdd is failing, dropping enough bits between the head and the system itself would cause weird freezes. if that's not it, try another motherboard.

[Jago]

This seems more like a power issue. Even a 750W PSU can pump out faulty power to the board, causing all types of havoc. If you can get your hands on another PSU, I'd try that first. If you're still having freezes, double check that the CPU and memory settings in the BIOS are correct. Especially check that they're not getting overclocked.

If possible, check that the power coming from the wall is also clean. I also had random freezes just like you described, only to turn out that the outlet was pumping out bad power. The area I lived in at the time was switching out power meters, and during that process the power was fluctuating like mad.

Best of luck!

[prophetik music]

psu would just restart the computer or freeze it hard-core, not allow it to continue displaying data that's changing (like the blinking memtest icon) or really output anything - like the audio. that makes me think that it's a mobo issue. if the hdd was dumping bits along the way, too, that might cause an issue similar to this as well. plus, if a mobo got stuck on something, it'd just hang on that audio sample that was playing and continue hammering it out.

bad power is only an issue if your psu doesn't have active pfc, which most corsair models do have. if your psu doesn't have a switch on the back to switch between 110 and 220v for power intake, it's got active pfc, and as a result can take anything from 100-240 from the wall without any issue. i had a similar problem with an old pos computer with passive pfc at my wife's house in the basement, which is over a hundred years old and has poor wiring.

[CSmith]

Thanks for your replies, guys.

I have two hard drives hooked up right now, the 500 GB main hard drive, and then an 80 GB one I'm using for swap space. They both tested fine with the Western Digital diagnostic program. The only other hard drive I have access to is a 160 GB external one. Since the computer has frozen a few times only a couple of lines through POST, could Windows actually have anything to do with it anyway?

My PSU doesn't have a switch on the back, so I guess it's okay in that respect. The thing about the memtest icon blinking is that, well, that + sign was the only thing moving. Progress bar, elapsed time, everything else was stopped, and of course the computer wasn't accepting input. Any time it has frozen in Windows, video completely stops. But the signal is still there because the image stays on screen and the monitor doesn't say "no signal."

My brother told me I should look around and see if I can see any broken capacitors on the motherboard, so I thought I'd give that a shot. Just trying to narrow the possibilities a bit, and I don't have any spare parts lying around except for the fan that originally came with the CPU.

[prophetik music]

windows might not have anything to do with it, but the HDD itself might.

i'm still leaning towards motherboard, but psu could be a possibility as well. the problem with stuff like this is that you basically just replace stuff until the problem goes away unless you've got an expensive set of diagnostic tools.

what are your system temps? get hwmonitor, a free diagnostic program by the makers of cpu-z, and get us a screen.

[CSmith]

Alright, here's the screen cap of hwmonitor. Took it a few minutes ago and the computer has been running with no problems whatsoever for about 6 hours now (which is becoming more and more rare these days). Just noticed, the GPU looks really hot compared to everything else, yet I'm not doing anything graphically intensive at all. Should it really be that hot? The video card has its own fan, but it IS right next to the sound card because the only two slots they'll fit in on the motherboard are right next to each other, so I guess that could hurt the circulation? And hwmonitor only shows speeds for two fans, but the power supply has a fan (of course) and I have another fan in the front of the case, and one on the side.

http://img64.imageshack.us/img64/184/screencapb.jpg

[prophetik music]

the gfx card is fine. they're made to run up to 100C with no problem. my 7300LE (for extra monitors) in my machine idles at 90C because it's fanless.

don't mind that it only shows for a few fans. it should show for every fan that's both hooked up through the motherboard (only fans connected through the mobo show up, so nothing for the psu or hardwired fans) and has a functioning third channel on the plug to monitor speed. who cares how fast they're running? as long as they're pushing air, they're doing their job.

i didn't see anything there that looked too crazy. the v-core looked a touch low, but i don't remember enough numbers about my old e8400 to compare, and i remember that it ran low when i had it. so i call this a dead end =(

[phill]

Since the computer has frozen a few times only a couple of lines through POST, could Windows actually have anything to do with it anyway?

You wouldn't happen to remember how far it go through POST would you? POST operations are very basic and if it is screwing up without BIOS errors, you may be able to limit where you are looking. For example, if it freezes during or just before the information about the hard drives is loaded, you may be looking at a bad HD.

Freezing on POST with a lack of BIOS errors may also indicate a bad motherboard as prophet has already stated.

[m68030]

I had trouble with a machine doingbthe same thing and memtest not running correctly. An older version of memtest worked and scrolled the screen with ram error. He problem was fixed was bumping up thr voltage on the ram a bit.

[CSmith]

Hm, I'm starting to think it might really be an issue with the power supply. Just now, I turned the computer on and the hard drives didn't spin up. 3 times in a row. Then the 4th time, they started to spin, stopped, the case LEDs turned off, then about two seconds later everything came back on and the OS booted up. Strange. Would that be a motherboard issue or PSU like I'm thinking it is?

[prophetik music]

that's what my computer does, all the time. but my psu is rock solid stable (and a good brand, seasonic x750 is one of the best 750w psus out there). i don't ask questions =)

[CSmith]

I had trouble with a machine doingbthe same thing and memtest not running correctly. An older version of memtest worked and scrolled the screen with ram error. He problem was fixed was bumping up thr voltage on the ram a bit.

I tried this finally, and it seems to be working! I upped the voltage by the smallest increment possible and ran memtest for a while them bumped it up some more. 1.88 was the breaking point, where I basically got the program title and the background colors but nothing else on screen. Dropped down to 1.86 and ran memtest for 6 hours (through 7 and a half passes) with no errors. I turned the computer on again this morning to check some things before work and left it on, and it's still running now, so that's a total uptime of around 11 hours so far.

Of course, I've had whole days in the past where it's run just fine, so I still have to run this thing a bit more to make sure it's not just a coincidence, but for the time being things look pretty good.

Thanks for your help, guys!