No video to monitor.

I have a Athlon 2200+, k7S5A pro M/B, 4 or 8 mg AGP card, 256mg 2100ddr ram, 350watt p/s, (GEM) 17 in. monitor.

I have put it together and when powered up I hear the initial post beep but get no video on the monitor. I can hear the floppy drive spin and also I think the HDD spin but no video on the monitor. I moved the ram to the other empty slot without improvement.I also had bought a new 128 mg agp card GFORCE 5200 and still no video. So I took it back.
Also tried a PCI video card 32mg ATI radeon 7000 which im using now in this PC.
I have unhooked everything eg: cables... hdd,floppy, cd, all front panel connectors exept power ( in an effort to reverse engineer). When re-booted I still got no video.
I am using the same monitor now on this P2 400.
I am not sure what is next to do. Any one out there know?????????
Please say yes.