Trying to fix grandson's computer. One long & two short beeps, no post on power on.
System: Asus A8N-SLI deluxe, AMD Athlon™ 64 X2 Dual Core Prossesor 4200+ 2, 2Ghz, 4 each Corsair CMX512-3200PT DDR Ram, Dual EVGA e-Geforce 7800 GT video cards, 4 Raptor SATA drives, PurePower 680 watt PSU.

ASUS Tech support said to repalced the memory, I did, no help.
Took board & PSU out of case and -*test*-('")ed with nothing (no video cards, no KB, no mouse) connected to MOBO except power cables and new set of Corsair VS1GB400C3 (2GB) in blue slots. BINGO, it powered up. Set to single video mode and inserted one video card. BIOS booted up no problem. Installed all hardware one item at a time until all back to normal. Still booted up ok, Put old memory back in and still booted up ok. Put system back inside case and BOOOMMM, beeps again and no post. Removed from case and started over. Now it is intermittent, clearing CMOS between each -*test*-('") seems to help clear the problem sometimes. During last BIOS setup it froze and got wired hex symbols in up left corner of sreen. Has not booted up since. Noticed keyboard lights acting strange. Suspect problem with PS/2 ports or CMOS bad.

Just finish reading your thread about same problem. Tested video cards in a friends computer and they both worked fine.

Can someone help? Is it the MOBO or the CPU?
If problem is MOBO what is a good replacement that will use the same CPU, memory & video cards.

Thanks,
Bud

Welcome to the forum Bud.

One long and two short usually indicates a video card problem.
The fact that you saw weird symbols and such at boot seems to support that.
Make sure that the video card is seated in its slot securely, and if it has a fan its working.
If possible maybe try a different card in the machine if you have another around to try.



edit*
I guess I should read more carefully as it seems you already ruled out the video cards.

Doubt its the CPU, and since you ruled out the video card I'd say its the motherboard. However, the fact that it didn't happen when you took it outside the case with little connected leads me to believe a few things. Either there was something being shorted out inside the case, or the PSU unit could be the issue.

If you want/need to replace the mobo, and stick with a 939 socket, there will be slim pickings out there. You might be able to find someone selling their A8N32SLI Deluxe, which is a very good mobo, at a good price.

Looks as your grandson has a very nice computer with some great componets. Now may not be a bad time to consider upgrading the mobo/cpu/mem as prices are really low right now.

Hope this helps.

When you set the system up outside the case:
1. Did you use the Purepower PSU to run it?
2. Did it boot OK with both vid cards mounted?
3. Did you use the same keyboard and mouse?


When you put everything back in the case:
1. Have you tried it with just the two new sticks of Corsair VS RAM? 4 sticks of RAM and 939 socket CPU's don't get along well all the time.
2. Have you tried it without the front panel USB ports connected?

This is all from my 50 yr-old memory so bear with me...

Not sure I would rule out the CPU just yet. I had the EXACT same problem a year ago with the A8N32 SLI Deluxe MOBO. Finally narrowed it down to bad RAM processors in the AMD CPU. Found that our by the great help from this Board and bought a cheap AMD 3200 CPU from the Egg, tried that and it worked! So I returned the 4200 for a new one (had to jump thru a few hoops at TigerDirect) and now all is well. I have been using the build since then with no problems.

Good luck and I hope this helps!

netcop

I have to agree with netcop, I had the same problem and it was my X2 3800 that caused it. Changed the cpu with a cheap 939 and presto she booted up and worked fine. Is your grandson overclocking at all?

Dub

There is some good advice above. If you will answer Merc's questions, that will go a long way towards solving the problem. I'll add a couple of more to try:

1) With the system mounted in the case, disconnect all hard drives and optical disk drives from the motherboard and from the power supply. Remove two sticks of RAM. If it starts cleanly in this configuration, shut it down and give the PSU 10 minutes to cool down. Insert the other two sticks of RAM and try again. If it still boots cleanly, shut down and let it cool again. While it is doing so, reconnect all of the drives. Let us know where it fails to start cleanly.

2) Check for missing motherboard mounting screws. There should be nine in the motherboard, if one is missing, see if it's shorting something out (sitting on top of a video card perhaps?).

3) Reseat the video cards and the selector card as well.