The motherboard doesnt have 4pin 12v? or you just arent using it?
the radeon 9800 has external power conntectors, make sure they're plugged in.
reseat your ram/proc/and cards.
no-post no-beep means the board is dead. Sometimes they can still light up, but not work. Try using a screwdriver (or other conductor) to power on your system instead of the switch, maybe its a bad switch. Make sure that your speaker is plugged in, so that you can hear beepcodes if there are any.
if that doesn't work, take the board out. make sure all the gold screw thingies are in their places, and not shorting out the board.
if that doesnt work, get a bigger hammer.
AMD 64 x2 3800 Venice @ 2.0
Zalman 7700 @ 28c
2 x Samsung 1gb DDR400 CL2.5
2 x eVga 6800 256mb GT
430mhz Core / 1.1ghz Memory
Sandra Memory Bench:
Sandra Cpu Arithmetic:
Eat your heart out intel.