My System
MB: Asus A8N-SLI (nForce4)
CPU: AMD Athlon X2 4800+ (socket 939)
RAM: Mixed Brands 4x1GB DDR3200
HDDs: 5 [RAID 0 Hitachi 1TBx2; RAID 0 WD 80GBx2; WD 120GB IDE]
GPU: BFG 9800GT
PSU: OCZ 600W modular

Problem
This morning I sat down in front of my computer and woke it from sleep mode. Everything was going well for about 10 or 15 min. then the video on both monitors went out. I was playing Minecraft at the time. I help down the power switch to shut the system off. I promptly rebooted the system and other than windows complaining about improper shutdown, everything seemed fine for about 4-5 min. when the video went out again. Subsequent reboots now result in no video.

What I've done so far
My first though was overheating. However, I've visually confirmed that all fans are spinning and free of dust. I swapped out the 9800gt with a 6800gt that was working when it was last in the system. The lack of video persisted.

What should I check next?

5/10/2011 5:53:24 PM

Has anyone ever had a PCI-E slot ever go bad on them?

This afternoon I'm going to try my video card in the second PCI-E slot to see if it works there. I'd have done that already but it requires me disassembling half the machine because the HDD caddy blocks the second PCI-E slot for long cards that require 6-pin power cables.

I'm also going to check if it will still fully boot even without video and give me a remote desktop connection.

5/11/2011 11:22:48 AM

I've never seen a bad slot, but I've had motherboards go out.

Do you have any bulging capacitors around the CPU or northbridge?

5/11/2011 11:59:35 AM

All the caps look fine.

5/11/2011 1:29:13 PM

Mind if I piggy back? Didn't want to create a new thread.

Recently one of my CPUs started booting up with aero disabled (Win 7 x64). The device manager shows Code 43 for my 8800GT. This all started shortly after updating to the latest drivers, so I reverted back to the old drivers and I still get the same issue.

Little more history. Bejeweled 3 started locking up the system. That's what prompted me to update the driver. It still locked up after the driver update, code 43 on a cold boot less than a day afterward. I've got a feeling that the Bejeweled thing was related to the wireless printer setup - long story - but maybe it was just another indication of a failing card.

I've googled a bit but found nothing conclusive. Most searches point toward the card having gone bad. Still it would be nice to know before dropping money on a new card. Got a feeling that I'll need to get one anyway, so if it comes to it what is the cheapest 8800GT near-equivalent?

[Edited on May 11, 2011 at 1:43 PM. Reason : -]

5/11/2011 1:40:58 PM

^ Reinstall the driver and make sure the fan is spinning on the card. Also, try not to jump into troubleshooting threads unless you're having the same or very similar issue.

5/11/2011 2:28:31 PM

Any beep codes occurring? Do you have a Windows Start sound configured? If you just let it run does it ever get that far without video? (meaning can you determine if everything else is working aside from the video?)

5/11/2011 3:49:09 PM

^ The MB doesn't have beep codes. It supposed to read out problems in plain english. I'm not sure if it works through the standard MB audio or if I need to hunt down a PC speaker to attach to the PC speaker pins.

This evening I'm going to see if it is still fully booting despite the lack of video. I'll post updates.

5/11/2011 6:09:11 PM

Update
Tried to boot the system a few minutes ago. It came up fine. I logged into windows. I was looking at my desktop for about 30 seconds and it reboots (as if the reset switch was hit). 2nd boot had the same outcome as the first. 3rd reboot resulted in no video and the system appears to be idling with the fans and drives spinning. The router doesn't show that system as an active client.

5/11/2011 8:22:45 PM

Does the motherboard have any built-in/on board video that you can use?

Also,

Quote :

"I'm not sure if it works through the standard MB audio or if I need to hunt down a PC speaker to attach to the PC speaker pins."

You'll need the PC Speaker connected to get any beep codes.

5/11/2011 8:39:29 PM

Update
I unplugged the computer from it's UPS and plugged it into a standard surge protection strip. It's been up for 10 minutes how with no signs of a problem.

I've only ever had the one UPS and it's always worked fine. Are my symptoms consistent with a dying UPS?

5/11/2011 8:44:24 PM

I was going to suggest PSU or something power related.... UPS could go out but I've never heard of one failing. If you have a UPS with dual-outlets, you may see if the surge outlets are working vs. the battery outlets... you may also try installing the software that comes with your UPS if it has any.. I know my APC tells me if there's something wrong with my UPS... how old is it?

5/11/2011 8:48:26 PM

UPS is 5 or 6 years old. My monitors are still plugged into the UPS and are working fine. They seemed to stay working fine even while the computer was having troubles. Of course, they draw a lot less current.

5/11/2011 8:52:21 PM

Fuck! I was editing my last post to say I wasn't sure where the UPS's communications cable was when the video went out again. All the fans and drives when through their usual reboot sounds but again the system isn't showing up on the network indicating that it didn't otherwise reboot.

5/11/2011 8:58:52 PM

And this is when plugged into not the UPS? Replace the PSU.

5/13/2011 10:37:58 AM

The PSU is brand fucking new. At least that means warranty. I'll have to verify that's the source of the problem.

5/13/2011 11:42:41 AM

I notice it's modular, you've checked and rechecked the connections right?

5/13/2011 11:49:52 AM

I have.

5/13/2011 5:28:00 PM

Update
I tried a different PSU: symptoms persist.
I swapped the motherboard: symptoms persist.

What's next? CPU?

5/16/2011 8:39:11 PM

Final? Update
It was the memory. The MB only outputs POST errors through the standard audio ports, not the coaxial port I was using for audio. I plugged in my head phones while it was trying to boot and there is the error clear as day.

5/17/2011 9:23:58 PM

So the PC Speaker didn't put out codes? I didn't know they'd also put out codes via the headphone/speaker jack.

5/18/2011 1:21:58 AM

My MB has some cool feature where POST errors are read out in plain English. As an example: Tonight I plugged in my headphones to the normal audio port and heard a recording of a woman's voice say, "System failed memory test" upon POST. According to my manual, I could even record my own POST error messages.

5/18/2011 2:18:48 AM

well awesome.

5/19/2011 10:52:35 AM

^^I ain't never seen no shit like that before

5/20/2011 5:24:40 PM

^haha, that's BALLER. I want one.

5/20/2011 6:16:00 PM