Random Odd Computer Lock Ups (Vista)

Hi there,

Recently I've been having some odd lock-ups on Windows Vista 32-bit.

It started when I was running Resident Evil 1 on PSX emulator (Don't flip people, I own the game, my PS1 just died).

Since then, I've done 3 or 4 complete reformats, but the problem persists.

The problem I can't seem to link to a specific issue, it happens under any type of use, light or heavy. I can stress test fine, yet using Firefox, it can crash (No specific websites), or my TV tuner, where when it locks-up, the sound starts stuttering rapidly.

The lock-up is that the screen freezes, I can't use Keyboard, Mouse, anything, except the Reset/Power button. Harddrive activity ceases.

I've used Seatools DOS Boot Disc to check both my Seagate 500 and 1000 GB HDDs, Short and Long tests passed.

I tried memtest86+ for 6 hours with no errors, and Window's version of a memory check for 6 hours with no errors.

Temps are fine, it isn't overheating, generally CPU is 42-45, and NB is 35-40

There is no rhyme or reason to these lock ups, as I've said, it just stops, if there's sound, it stutters, no mouse/keyboard, and no HDD activity.

It can happen from every few hours to once every few days.

Can anybody please offer some ideas? I'm at wits end here.

Any input/advice appreciated

Here's the specs:

ASUS P5N-D Motherboard
Intel Core 2 Duo E8400 (Stock)
2 GB Kingston DDR2 667 (Stock)
Ultra LSP 750 Watt Power Supply
Seagate Barracuda 500 GB (OS)
Seagate BArracuda 1000 GB (Data)
2 XFX 8800 GT Alpha Dog Edition Video Cards (Stock)

I just recieved one moments ago with Task Manager open, and nothing seemed to be out of the ordinary, 950 MB of RAM was being used, CPU was 10%, Page File was 1114/4332M, at the moment of crash.

Can anybody help me find a solution, or even just single-out the problem?

I was leaning towards bad PSU and those numbers confirmed it.

Apparently Speedan may not be so accurate, Motherboard and Asus Probe II say that everything is normal. Any other ideas? Runign Prime95 now

That's the issue, the windows logs say nothing, except for when I had to do a hardboot, it saw it as an error. Its like the system doesn't know it has a problem at all, but recognizes when I manually reboot.

The problem came on suddenly, with no hardware changes, just happened once, and ever since.

There are no bluescreens, everything just suddenly stops.

Even Performance/Reliability Monitor says nothing.

So I have very little to go off of :\

A development, I just got another Lock-Up, when using my TV Tuner with VirtualDub. The system got incredibly slow, but mouse was still moving, nothing was really responding. Only after a minute or two of this did the complete lock-up occur.

Tried 2 different BIOS revs., 1001 and 1101, no difference.

Running stock too, which is odd. I never had these issues before, but that board was RMA'd, this new one is when it started, but ran fine for 2 or 3 weeks prior, though, when I think about it, I don't think I had left it on as long before (Again, only happening after long use).

I'll try to OC my ram to 1:1 though, thanks