Welcome to the AT forums, AMDIntel.
I'd suggest you go and read up at Mechbgon's site linked above. If you've got all the points there covered, then check t his:
Boilerplate-01:
. Common causes of failure to boot (no video, no beeps) assuming PSU isn't totally dead:
1- RAM, CPU and/or AGP video card not seated properly, a bent pin or corrosion.
2- Drive data cable on upside down or only on half the pins or shifted a pin or two (usually Floppy or Zip drives).
3- CMOS needs to be cleared (AC power must usually be disconnected or . attempts to clear CMOS may fail) Unless your mobo does not use a power-off CMOS clear - check your mobo manual for specific info.
4- On some new mobos there is a CPU protection feature (esp. on Asus/Asrock Athlon/Socket A mobos) that will not allow the system to start if there is no fan (or a fan without a working speed sensor wire) connected to the CPU Fan power connector on the mobo (specifically marked "CPU Fan"). If you tried to start your machine without a fan properly connected, you have to attach a proper and working fan and clear the CMOS before it will boot.
Just as an aside, I'm no fan of Value Ram. I've had two of those fail on different occasions on my own machines (sample size: four modules) means a 50% failure rate in my hands. I don't recall EVER having a Samsung or Micron/Crucial module fail.
.bh.