Random crashes

Hi ive had my computer for about 2 years now and it keeps on crashing all the time, often it will freeze instantlly with the sound still in the background looping like a broken record player.

sometimes the computer will just gradually grind to a halt, ill be in I.E for example and go to switch tabs where it will just freeze half way through. I can still move the mouse and if i click another application from the start bar but that wont load fully and after about 20 secs or so everything locks up completelly.

when i first got it, it used to freeze always when playing Full screen video or games after a couple of hours, since then ive replaced the motherboard twice the graphics cards once and the RAM once

Now i can watch multiple films in full screen or have World of warcraft loaded for hours and no crashes but as soon as i Alt Tab or try to use applications simultaneously the chance for a freeze increases

Ive done multiple reformats trying both XP and Vista 64/32 with no effect so i assume it must be hardware related?

The current setup is:
790I ultra
E8500
2GB DDR3 Patriot 1333MHZ ( This was 4GB but it seems more stable when only using 2)
GTX280 X 2
1 kilowat PSU

I used nvidea system monitor to check temps and graphics /CPU hover around 40-50 c while mcp is 60 and system is 30 c so i dont think its overheating?

The fact that it becomes unstable when i add the other stick of ram and it FAILED to run memtest (crashing midway when i left it overnight) makes me belive this is the cause.

However before i go ahead and buy more RAM sticks do you think this would actually solve the problem?

 

If the ram failed memtest, then yes i would suspect dead/dying ram.

Does the 2GB you got now fail memtest?

Are those temperatures idle or load? Ie in game or out of game?

 

yeah both sticks failed memtest so im gonna buy new RAM as soon as i can afford it

Also what about the harddrive, could that cause crashes, its around 2 years old now and im sure it makes revving noises sometimes

 

Normally what happens when you have bad bits in the memory sticks, is that data is written erroneously to the HDD.

Have you also tested the HDD?

Most likely your freezing issues should stop after the RAM is freshened up, but I may be mistaken. You may even want to do a repair, or fresh install of you Operating System, just in case.

How hard are you pushing this PC?

I have had Crucial Ballistix for a couple years, with no issue yet, but I really don't push my PC that severely...