I press the power button, the fans start up, everything's going, but no beeps, no error messages, not even a signal sent to the monitor. I just bought a brand new Soyo SY-K7VTA Pro V1.0 motherboard with an AMD Athlon XP 2400 processor, and i put in my old 256 MB mWave memory, a network card, and my nVidia GeForce 2 MX video card. My hard drive is a Maxtor 7200rpm 20 GB. It has everything from my old computer still on it (OS and all).
After nothing happened with this setup, I took out all my cards, memory, etc. I also disconnected all the IDE cables and all the power cables, excpet for the power to the motherboard. Still nothing. I also tried different combinations of cards and IDE and memory in hopes of isolating the problem. But still nothing. Any suggestions?

This might be a pain but double check all jumpers listed in the manual, and make sure on the back of your PSU its set for 120 not 240. Also take a second or third peek at your RAM, make sure its pushed ALL the way down and in.

Is the hard drive spinning up?

i had the same prob with a P4 board,,it turnd out to be uncompatible CPU,, i dont know too much about AMD though.

Went to Soyos website, clicked on "Maximum AMD CPU Speed Support" and this is the details for your mobo:

It wont take Barton cores. Can you get 2400's in Palomino cores? If so maybe you have one of thoe jophus. If thats the case you can either toss the CPU and go buy anohter one (just make sure its a Thoroughbred!!!) or get a new mobo.