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I recently bought another video card hoping to squeeze a couple more years our of PC gaming but have since had a major system malfunctions. My current situation is that the computer does not seem to post (nothing on the monitor). I checked the video card and also the previous card on another computer and it seems to be ok. I have also tried new RAM which was sitting around in its original package (unused). Nothing. I get no beeps or anything. After a few seconds or a few minutes the computer will power off. I tried a known working PSU and it does the same exact thing.

One thing that I noticed is that the SB green LED on the motherboard is on, however when I disconnect power from the wall to the PSU, that light goes completely out in a matter of 2 seconds. Is this synonymous with system board failure? Or is there perhaps anything left to check?

I have hooked up my digital multimeter to the 20pn ATX power and each connector pin tests within the correct voltage, I even checked the CPU and reapply a light coat of thermal compound. Nothing seems to work.

I am not very experienced with motherboard troubleshooting as I usually by ASUS and have had nothing but luck with them. this one is at least 2 years old, could it just be at the end of its life?

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A few targeted checks will narrow this down quickly. The green SB (standby) LED only shows that the board is getting 5V standby from the PSU — it does not prove the CPU rails, VRMs, or BIOS are OK. That means the symptom you describe is consistent with several failures (bad CPU 12V feed, VRM failure, short on the board, corrupted BIOS, or a missing speaker so you get no POST beeps). has already swapped parts, so focus on isolation and direct checks next.

Try these bench tests in order, with the board out of the case on a non-conductive surface and anti-static care:

  1. Remove all cards and drives. Fit only CPU+heatsink+fan, one known-good RAM stick, PSU, and a system speaker.
  2. Verify the 4/8-pin ATX12V CPU power connector is present and delivers +12V when you try to power on. The 20/24-pin showing voltages does not guarantee the CPU rail is OK.
  3. Short the front-panel power pins (momentary) to rule out a faulty case switch. Watch fan spin, listen for beeps. If there is no speaker, add one — no speaker = no beep codes.
  4. If still dead, swap the CPU into a known-working board or try a known-working CPU in this board to separate CPU vs. motherboard failure.

Also perform a visual inspection for bulging/leaking electrolytic capacitors (around the CPU power phases and southbridge) and smell for burnt components. Reset CMOS by removing the battery and using the clear-CMOS jumper for a few minutes, then replace the battery. ’s suggestion about the BIOS chip can help in some cases, but chip replacement/flash is advanced.

If the board shows no 12V on the CPU connector or has visible VRM/capacitor damage, the most practical option is repair (recap/VRM repair) or replacement. If uncertain about voltage checks or component-level diagnosis, have a local repair shop bench-test it to avoid further damage.

Member Avatar for mechbas

There's a distinct possibility that the new GA that you installed has overloaded the PSU's wattage capacity?
Stick the old one back in (if it still works) and see what happens.

Member Avatar for jack_morgan311

have tride 2 known working PSU with the old graphics card original configuration) and have the same symptoms. i checked the amperage on each part of the psu and ave not exceeded the wattage as per both PSU specs.

Member Avatar for mechbas

>>>Is this synonymous with system board failure? Or is there perhaps anything left to check?
The board failure, if that's what happened, seems a bit premature. Left to check? From your pov probably not. such checks can only be done at the mfg. ass'y. line.
What I meant at the wattage notation was that there is a possiblity of "too little" of it. The resultant drain creates heat, easy to see where that goes. Your soldering iron works on the same principle.
No beeps means you're not posting. You might want to try a new loaded bios chip which may help. Otherwise, your suspicion that the board is basically gone is probably right on.

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