I have a similar problem, with an ASUS A7v266-E motherboard, which does not appear to have on-board video. Athlon 1900 CPU, Crucial 256 DDR Ram (only 256 for now, as I blew the wad on all this stuff). I'm building my first computer, bought Larry's PDF file on how to do so.
I have studiously checked all jumper settings, changed the video card first from the original ATI xpert2000Pro to my own PC card, ATI Radeon (both of these were AGP cards) and now have a GeForce4 MX 420 in the #2 PCI slot (I read that PCI slot #1 shares something with the AGP slot next to it).
Here's what I can see of what's working and what's not. The power supply fan is working, though I'm not sure why there was nothing to plug into the board specifically for the fan in there. The CPU fan is working, as is the onboard CPU cooler. The case fan is working. I can feel that the hard drive is running. The case power switch and the light on the floppy drive work. As I plug in the keyboard, the keyboard lights go on, but they do not work once plugged in (if, for example, I hit Num Lock).
I just get nothing on the screen at all. It is a working monitor. I also get no beeps at all, even if I remove the graphics card to instigate beeps. I plugged a speaker in & again, I can hear the electronic sound it makes plugging in, but have heard no sounds once plugged in. The board has on-board sound. No beeps before I plugged in speakers, either. I tried the Western Digital Data Lifeguard Tools that came with my new HD. Nothing happened on the screen though the floppy light went on (did not blink).
Does this (admittedly long) note tell you experienced people out there just what is amiss? Thanks so much.