Persistant problem

Wonder if anyone could help me here because I'm at my absoulte end. I've been having reoccuring crashes both in Windows and Games, more frequently in games though. There is no consistance in the likelyhood of the crashes and freezes they just happen as and when and when they occur there's nothing that can be done apart from restart the system.

System Specs;

Athlon XP 3200+
1GB RAM
Gainward GeForce 6800GT Golden Sample (AGP)
3x HDD (1x160GB (Backups), 1x40GB(Programs) ,1x 80GB (System))
(BF2 is running on the system disk)
Soundblaster X-Fi Fatality
CD-RW Drive
DVD-RW Drive
580w Hiper Type-R PSU

I have tried everything to remedy this and am frankly lost now.
First I thought it was the new HDD I had installed. So I removed that put the old one back in, reinstalled Windows and the problem persisted. Then I tried both graphics and sound drivers, rolling back, updating cleaning completely and reinstalling and still the problem has pervailed.
I then thought RAM may be the problem, so I purchased a brand new 1GB of RAM (Corsair XMSPro PC3200) which seemed to solve things temporarily then the problem returned.
I then read somewhere about Gainward's graphics card software (Expertool) causing problems with BF2 (which is the game that I primarily play), so I removed that, installed a new cooler for the grpahics card (Zalman VF990cu)which is running the card approxomately 20oC cooler than it was with stock cooling.
This seemed to rememdy the problem for a little, allowing me to play problem free for a day or so but now the problem has returned once again.

I've been through 3 Windows re-installs, numerous driver re-installs, two new parts and 3 different Hard Drives trying to sort this and I've run out. Nothing I try works and the problem still continues. I am *this* close to just forgetting about PC's altogether, but there's nothing I can see that's causing these problems and no consistance that I can latch onto and delve.

If anyone has any even the smallest insight I need to know. If you need anymore information just ask.

take the x-fi out and get rid of all the creative stuff and then see if it still does it. what motherboard is it?

Try running memtest - memory could be bad, or the timings could be wrong:

http://www.memtest.org/

yeah I would try memetest aswell as it seems there si a problem with your memory

you could also try underclocking the card to see if its on its last legs, it may hold up a few days/weeks once underclocked then start acting up again until you underclock more..

i had a problematic 9800 that lived on just fine with a P4 fan resting on the back of the card to keep it cool..

The graphics card was always clocked at 400, 1100, which is what it was it's guarenteed to run at under Gainward's "Golden Sample" and has always run at those clocks. But is currently running at 350, 1000, (Which are standard 6800 clocks I believe) and still does the same thing. Also it's currently idling at 47oC which I think is fairly cool for a 6800 so I don't think overheating is the problem.

The memory is running at 2-3-3-6 which are the clocks stated by Corsair, but I'll grab memtest and get it going overnight to be double sure, I'd be pretty annoyed if brand new RAM is bad though.
[EDIT - I ran memtest86 for an hour (2 complete passes) with zero errors, so I think I can safely eliminate the RAM as a problem]

I'll try completely removing the X-Fi and software although I'd be lost if that was the problem as I'm really pleased with it.

Thanks for the suggestions though, thing is I've thought of most of this stuff and tested it already. My worry is the fact that non of the problems were present over the year I've had the system and have just started to happen recently.

I somewhat suspect the board as it's not a choice component, I was forced to change to it due to circumstances and havent' had a chance to upgrade since, (but will at the end of this month.)

The mainboard is a Gigabyte GA-7N400S-L.