First my spec:-
AMD64 San Diego 3700+
2x1gb corsair xms 3200 c2pt
HIS Excalibur x850xt turbo
Asus A8N-E nforce4 ultra mobo.
I built this PC just under a year ago. I noticed that in games such as WoW, during play the game would freeze then after a few seconds the screen go blank like the monitor was in standby (light would go from green to orange).
Thought perhaps maybe I had some dodgy RAM so I used memtest on it and all was fine, so thought perhaps a dodgy card. The problem rarely happened however so I thought nothing of it.
Come January this year, I downloaded a quake 4 demo. As soon as the demo started up, my computer restarted itself. From this point it would not start up most times - no display on the monitor and the bios POST going 'beep...beep...beep...' repeatedly. Sometimes however (although very rarely) I managed to get into windows and it could work for random amounts of time (worked for a whole day at one point) but eventually would just restart itself and the beeps continue. Tried a friends RAM in it and same result.
I therefore played about with the RAM and with one stick in third slot, it worked absolutely fine. However I noticed if I had a stick in the first slot, would rarely boot, beep...beep... all over again.
It worked pretty much fine like this, though during games I got the random freezes, screen going blank again, but not very often. Nothing really too annoying though.
At about Easter time, the same problem again surfaced during a game of WoW. Screen went blank, would not boot, 'beep...beep...' all over again, so I removed the stick of RAM and put in the other one and it worked fine again (still though random blank screens during gameplay).
Fast forward to last week, during WoW, I got the blank screen yet again, so as usual had to reset the computer but then no display at all and 'beep...beep...'. Swapped the other stick of RAM back in, no luck. Put the other one in again and it worked fine (yet a minute earlier it wouldn't work at all).
However then I couldn't play WoW for a long period at all, maybe 5minutes-half hour before it's 'beep...beep...' time again. To remedy the problem I simply remove the stick of RAM then reinsert the same stick of RAM and it works again (really weird...).
I ran prime95 for 10 hours, ran fine, no errors. The computer was absolutely fine as long as I didn't go into games, so I thought it could be a video problem but then there is also evidence which points to it being RAM as I outlined above.
I tried a memtest again, went out, got in a few hours later greeted by a screen of all sorts of weird colours, memtest saying something about an interrupt, so rebooted...
Also then BSODS started to appear about fault in non paged area and irq not equal or less mainly. These would appear when the computer (rarely) booted up and I was doing nothing but browsing the web.
I did wonder if it were the PSU - the bios and Asus PC probe reported the voltages well within the limits (Enermax noisetaker 535w PSU) though PC wizard and motherboard monitor reported different voltages on the +5v and +12v well below what I would call 'safe' - so did make me suspicious maybe about the PSU.
Taking my bets that it was the motherboard, I ordered a new A8N-E. Put that in 30th August, and everything worked fine that day, not a single problem - both sticks of RAM in too which I haven't been able to do since January. However now every day I have woken up to switch the computer on - blank monitor (light is green though not orange), no POST beeps or anything but lights all on and fans etc going round. After resetting it a few times it finally boots and no problems what soever. If I restart the computer, restarts fine, if I shut it down for a short while, it will reboot fine. Problem only occurs it seems after it's been off for a good few hours due to me being asleep. Apart from that, no problems.
Again just examing the voltages - Bios and Asus PC Probe gives fine voltages, but PC wizard and motherboard monitor gives low voltages on the +12v and +5v line, though they are better than what they were with my previous A8N-E.
Was I unlucky in getting another weird motherboard? Or perhaps both the motherboard and PSU are dodgy and replacing the mobo only made the situation better and I must still replace the PSU.