PC freezes/locks up/hangs intermittantly - What hardware's responsible?

Hi, I've been having trouble with my PC itermittantly freezing and am having unsuccessful attempts to diagnose the problem. I've search high and low all over the internet, and can't seem to match my problem to anyone else's.


During these freezes, the PC just locks up. It won't respond to any inputs, the mouse freezes, it doesn't generate any outputs and I have to restart using the "reset button ". I also haven't installed any new harddrive recently that would have caused a new conflict issue.

To my knowledge, this problem has started fairly randomly.
Though it has been known to freeze when I'm doing absolutely nothing, this is a list of times when

It'll always/usually freeze:

Browsing hotmail
Browsing any flash-intensive site
Playing .avi files (trailers). Affects winamp, WMP, Zoomplayer...
Scanning with any anti-virus (AVG, McFee housecall)
Leaving taskmanager and playing MP3s seems to make the system more unstable, though doesn't seem to freeze it automatically.
Checked device manager. No obvious conflicts.
Will also crash in photoshop and flash, when handling large pictures.

Here are my attempts to sort out/diagnose the problem:

This began in Win 2k. I formatted my harddrive and installed XP on it. During XP installation, my computer locked up twice. Eventually installed XP and problem remained (unsprisingly)
I've reseated RAM, Graphics card.
Run PC with sides on and off - this seems to make no difference to stability and suggusts it's not an overheating CPU problem. CPU reads at around 35-45 centigrade.
Ran a CPU burn-in test, came up with no problems
Ran Chkdsk, no problems
Ran Memtest86, no problems.
Took out my older stick of RAM (128), problem still persisted.
Ran ad-adaware and have run virus scan in past (problem seems to have got worse, inability to scan is a more recent development.)
Run in Safe-Mode. Still freezes.
Ran graphics test (lots of fast moving, rendered circles for a long period of time) and no lockup.
Increased paging file size (to 1gb)


...And I think that's all I've done (phew!). I'm definately suspecting a hardware problem, but not sure whether it's RAM or Harddrive.

On the note of the Harddrive, though no errors come up during chkdsk, it is /very/ slow: Read speed average of 5.74 MB/s and a write speed of 3.71 MB/s. If my pc is running out of resources, and is trying to use the paging file, will this slowness of read/write speed cause the PC to lock up?

If not, any other thoughts on what my problem is?

My system specs,

Pentium 3 1ghz
Geforce MX 400
384 MB of RAM (256 crucial, 128..nondescript.)
BIOS name: Award modular Bios v6.00PG
Motherboard: Model: 6A69RM49 Vendor: Micro-star international Co., LTD
Chipset Model: Intel 815 (solano) chipset

I'm completely stumpted here. I'm pretty new to all this stuff (having only actually looked into them when the problem arose..), so would appreciate some help from the experts. I'm terribly sorry about the length of this post, I just wanted to make available all the information I had.

-Jess (in desperation)

 

Hi

There are many things that could be causing your problem, and it does sound like hardware and not software. As a PC techo, i have seen the same symptoms in a PC caused by a dozen different things.

You have done the first lot of things i would have tried, and it would time to strip the PC right down, and try adding back hardware piece by piece until your problem came back, assuming it went away by stripping it down.

Take out or disconnect all non essential hardware and see how it goes (ie sound cards,int modem, network card, CD or DVD players, and any secondary hard disks) and also unattach any non essential external devices like printers, dsl routers, scanners. Non essential meaning you dont need it to boot the machine into windows.

To boot you will only need 1 bootable hard disk, power, video card, ram, a keyboard, mouse and the motherboard.

Anything further to this is best done by a technician as they will have access to replacement parts for every part in your PC to test with. So i suggest it is time to see your local techo! Your problem does sound like something overheating, but it could even be a chip or connection on your motherboard doing this, and it may not be obvious.

I have even seen faulty keyboards cause your type of symptoms. And you wouldnt think so would you. If i had to say what most often causes this sort of symptom, i would say overheating video card or faulty RAM. If you can, get your hands on another RAM chip and use it alone with both your existing chips out of the PC. Try both slots too seperately, as faulty slots can cause this.


Sorry i couldnt solve it, but your problem can be caused by too many things to write about here. See yout techo! Keep us employed lol. You may do more damage trying to fix it yourself.

 

Put the old RAM (128) back in and take out the newer RAM.

I'm wondering if your HD is at fault. Borrow beg or steal another drive. Take out the existing one, install the replacement and partiton, format and install XP again. See if that helps.
I recently diagnosed a LOOONG!! standing fault with an old system, that I had tried EVERYTHING like you have. I finally diagnosed that the system occasionally locked solid when the HD came out of spindown. Sometimes as the drive woke up it would freeze the PC solid. I turned off power management for the HD so the platters don't spin down and it doesn't lock now.

 

Thanks for the advice, I'll give some of it a try when I have time later on today. Got some spare RAM and a harddrive, hoping this will sort it out.

 

Well, tried replacing RAM and harddrive with no luck.

However, in a proper scouring of the motherboard with a torch, I found several bulging capacitors that don't look very healthy.

 

That's your problem. I guess they are the caps near the CPU? If you can replace them yourself it will only cost a few dollars. If not then get a quote as it may be cheaper (considering all things) to buy another board.