Very strange POST problem..

I bought this:

AMD 3200+ 64 bit CPU
1gb Crucial DDR 400 memory
A8V-MX motherboard

I connected this to my existing 160gb Barracuda Seagate HD and my CDWriter and DVD Drive.

The computer boots up ok. However, whenever i reset the machine or reboot through windows, the system doesnt POST. No beep. The CD Drives light up for a couple of seconds and then nothing. Nothing appears on the screen either. If i power down my PC and then switch it on again, it boots up ok. So the problem only seems to happen when i restart the machine. If its a cold boot (machine is off and then switched on) it works ok! Strange eh?

I tried removing some components i.e. cd drives, used 1 stick of memory etc. but nothing.

The only thing i can think it might be is my power supply. I am using a 400w Q-Tec power supply which has a 20 pin motherboard connector. My motherboard wants a 24 pin connector. I checked the motherboard manual and it said you can use a 20 pin connector as long as it is at least 15a on the +12v. My PSU is 16a. All the fans and lights are all working and there is no indication there might be not enough power. I am going to buy a 20 pin to 24 pin convertor to see if it makes any difference. If it doesnt i dont know what to do. I dont want to spend money on a new power supply if it doesnt solve the problem. Any ideas why this might happen? I looked around and cant find anyone who reports this same problem?

This sometimes happens. When the computer boots, listen closely, and check if you get a click instead of the usual beep. This indicated a memory problem for me. However I suppose it could be a PSU problem. Try different RAM modules, and post back!

yep the 2x2 connector is plugged in the correct spot on the motherboard.

I have a v770 32mb Viper graphics card and wondering if that could be responsible. It worked fine on my old machine though.

i had this problem once and it turned out to be a faulty video card...i don`t know whether this is your case.......sametimes it just refused to boot...unplugged ..and then it was ok...
it was a athlon2200+ xp, acorp kt333, and fx5200.......after changing the video card with a ati 9600 pro it all went ok................
i hope my experience helps you

problem solved! it was the graphics card. the mobo comes with an onboard graphics and i think it was conflicting with the graphics card. i took the graphics card out and the machine worked fine.

thanks to all who replied!