Frustrating Issue; Please Help!!!

I've posted this problem a few places already, but it's getting quite disorganized since I've tried a lot of things. Any help would be greatly appreciated.

It all started a week and a half ago. I bought a 9800 GT graphics card off ebay in anticipation for Starcraft 2. It arrived last Monday. I popped it into my system and loaded everything up. My system seemed to POST just fine. I went to log in and my keyboard didn’t work. Strange.

1. I switched my PS/2 keyboard out with a USB keyboard. The USB did not work.

After returning the keyboard to a neighbor I came back and the system worked again. I tried the graphics card a second time with the same result. Time didn’t solve this issue. I resigned myself to upgrading my aged computer. I bought it from a homebuilt computer store that did not use quality parts. Last Tuesday I put in orders to newegg to replace almost everything.

2. I took apart everything and let it sit overnight in boxes. The next day I put it all back together and the system worked.

The new components arrived and I assembled everything. These are my system specs:

Mobo – ECS G31T-M7
CPU – Intel Pentium Dual Core E5400
RAM – Kingston DDR2 ValueRAM (2x1GB)
HDD – Seagate Barracuda 250 GB 7200 (from old system)
PSU – Corsair CX400W

I used the same case, the same hard drive, and the same dvd drive.

Everything installed and worked great.

3. I tried the GPU with my “new” system after loading all the motherboard drivers and making sure xp transferred ok. I encountered the same problem – my keyboard didn’t work.

4. I took out the GPU and tried breadboarding. Neither the old, terribly cheap PSU worked nor did the new one. I installed everything back into my computer and it mysteriously started working. The keyboard functioned and everything.

5. I attempted the GPU one more time after trying to download the drivers. No success.

6. This time, I removed the motherboard entirely. Then, I put it back in the case, loaded everything up, and it seemed to work fine.

Those who responded to my previous post suggested a short to the motherboard. I researched the issue a little more online and found some other stories where keyboards didn’t work due to a motherboard short. I AM REASONABLY POSITIVE THIS WAS THE UNDERLYING ISSUE.

I ordered a new case since the old case was from the same store with the cost-cut parts. I bought an mATX case from newegg and it delivered yesterday. I also bought a corsair 650W PSU as the first piece of a gaming computer I’ll put together over the next 6-8 months. The computer worked all weekend without any troubles.

7. I installed the 650W PSU and the keyboard stopped working again.

8. Put in the 400W PSU and the keyboard still didn’t work.

9. Mounted all components in new case with new PSU. Keyboard still doesn’t work.

10. Breadboarded system again. Keyboard still doesn’t work.

11. Examined Mobo. Nothing seems to be out of place. On the back there is one tracer near the top (when mounted) that is gold colored instead of green. Problem?

12. Found the post detailing a proper breadboarding. I also found the Mobo slightly bent due to the processor fan, so I plugged everything and let it sit overnight (note, the thermal compound was ALMOST leaking into the CPU case. I removed it and found no leaking. Close call. I cleaned off the remaining compound with a Q-tip).

13. After sitting overnight, I connected the motherboard speaker. I only connected the CPU and fan. When jumping the power, I got 3 short beeps. I don’t know what they mean since several google searches couldn’t find ECS beep codes (not in the mobo manual).

14. I connected one Ram at a time. Each time the system would start without any beeps (there was a click noise that seemed to come from the speaker, but it also made that noise when the system shut down).

15. Put in keyboard, mouse, monitor, and HD. System loads without any beeps.

16. I booted while switching the CMOS jumper. Nothing showed up on screen. When I put the jumper back I got two short beeps. Keyboard still didn’t work.

Things I have ruled out:
PSU – the 400W works and the 650W powers the system up to the login screen. I don’t have access to a multimeter, but it’s getting the same results the 400W gets right now. This is consistent, so I don’t think it’s the problem.

Keyboard – This is NOT a keyboard issue. The keyboard lights flash on whenever I turn on my computer. When the system sporadically works, the keyboard works too. When I try to do something new with the hardware, the keyboard stops working. This is a hardware issue, the keyboard problem is just a symptom.
I have not ruled out:
CPU – I don’t have another working computer where I can switch the CPU.

Motherboard – I have a feeling this is the culprit, but since Ican’t rule out the CPU I can’t rule out the motherboard.

Keep in mind:
I can’t enter BIOS when my computer isn’t working. The computer doesn’t recognize ‘DEL’ and whenever I clear CMOS it does not automatically come up.

I can’t enter safe mode since I can’t enter BIOS nor press F8. You need a functioning keyboard for that.

I can’t use the windows boot disk since my BIOS isn’t configured to boot off disks and I need to press keys to initiate a repair install.
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With that, I open the floor to suggestions. Personally, I think the issue with my old case was bad grounding. Both motherboards spent time in the old case; they both experienced the same conditions. Is it possible for shorting to destroy a motherboard like this? Should I RMA the new board and try a fresh one (another problem since I’m moving 900 miles in 4 days, then 900 MORE miles 6 days after that)?

Please help!

Just to be sure, but have you tried the keyboard on other computers to test if they work there?

Typically, the only reason a PS/2 keyboard doesn't work is a bad connection, bad mobo or bad keyboard.

USB keyboards may require entering bios first to enable them.