Jam, How do I tell if I have socket A, 754 or 939? Like I said I know nothing about AMD. It's an Acer Aspire model AST160-US321H. The documentation that came with it tells me nothing. Their website tells me nothing. All I know is that it's an AMD320+. The fans turn on when I power up and that's it. No beeps, no hard drive activity, not even a power button light. I have removed everything from the board and tried booting with just one stick of ram (ddr400 256mbx2) and the hard drive. I have replaced the power supply with a brand new one, cleaned all fans and heat sink and removed the cpu and reinstalled. I am almost 100 percent sure that it is the motherboard. Could be the processor or both. The unit was quite dusty when I took it apart and it is possible the board or cpu overheated. So what I would like to do is replace the board first and see if that works. If it doesn't then I will replace the CPU. Problem is I don't know AMD. So I don't know if it's a socket A, 754 or 939 or AM2 socket F or S1 or what. I have never used AMD myself but I bought this system for my wife because it was complete and it was all she needed. Can you please help me find the best option to replace the board with one that would be compatible with what is already in the system? If any other info would help please let me know.

If you'd have simply looked at the socket when you had the heatsink off, you'd have you answer: http://regmedia.co.uk/2004/06/07/at... I googled you Acer model number & it appears the board is a socket 939. I don't know why you removed the CPU but did you thoroughly clean both the bottom of the heatsink & top of the CPU & then apply a tiny dab of paste before reinstalling the heatsink again? Like this: http://www.arcticsilver.com/images/... "The fans turn on when I power up and that's it. No beeps, no hard drive activity, not even a power button light" Still sounds like it *might* be a power problem. Are you sure the new PSU is adequate? How many watts & what are the amperage specs? You have the 24-pin plug & the square 4-pin plugged connected to the board? You don't need the HDD connected to troubleshoot. If fact, you should unplug as much from the board & PSU as possible. Externally, all you need is the keyboard & monitor...unplug the mouse & any other devices. Remove all cards except video. Unplug all drives (HDD, optical & floppy). Remove all RAM but one stick. Double check all your connections, make sure the CPU fan is connected to the proper header & click the RAM in & out of it's slot a couple of times to clean the contacts. Now see if you can boot up & access the BIOS. "If my answers frighten you then you should cease asking scary questions" - Jules Winnfield (Samuel L. Jackson) in Pulp Fiction

Normally the socket number is written on top of the socket, over the covered part of the ZIF lever. You'll have to remove the cpu heatsink in order to see it. But I think it's a 939. If you replace the motherboard and expect to use the existing OS on your hard drive you'll need an exact replacement. Just another 939 socket motherboard won't do it. XP will see the different mobo and give you a blue screen.

Thanks for the responses guys. I'll try your suggestions jam but I'm pretty sure it's the motherboard. It's not the power supply. I replaced a 300 watt with a 350 watt antec with more amps than the original. If it turns out to be the motherboard can anyone recommend a board that would replace it that has onboard video. I do not need good graphics on this computer. It needs to accept ddr400 and a Sempron 3200+. I am not concerned about losing xp, I'll deal with them after I get to boot.

Try removing the RAM. If you get error beeps, the motherboard is probably ok and the RAM might be bad. Also, there is a miniscule possibility that a defective hard drive could cause the problem. Disconnect the hard drive just to eliminate that possibility. You don't need a hard drive to get a display.

I tried all of this and still nothing. Thanks for the help though because I pulled the CPU again and it is a socket 939 so now I know what I'm looking for.

Don't over look the ON/OFF switch when trouble shooting.... Keep the old stuff running