Great thread here, I'm in a similar situation myself, no video, any help is greatly appreciated.
BIOSTAR GeForce 7900GS
x2 Kingston ValueRAM 1GB
It seems to POST, I get numlock and I can soft reboot from keyboard, I.E. ctrl+alt+del, all fans/lights work, power button shuts it on/off instantly. Originally I was getting beep codes of two long, pause, four short however through the course of my trial and error I reset the CMOS, now it is two long tones i.E. bad date/time from the reset.
The strange part is that my monitor acts as thought it is being sent a signal, it comes out of standby mode, however nothing appears. My thought on this is that the mobo is PCI-e 2.0 however this is not a PCI-e 2.0 card, does anyone know if there are legacy issues there?
Wikipedia has the following to say about PCI-e 2.0:
PCIe 2.0 is completely backwards compatible with PCIe v1.x. Graphic cards and motherboards designed for v2.0 will be able to work with v1.1 and v1.0, and vice versa. In some rare cases it is possible that a PCI-E 2.0 card will not work correctly on a PCI-E 1.0a slot. This is only limited to certain video cards.
Also I have tested with another 5000+, another M3A, another 7900GS another DIMM of Kingston 533 and an Antec 380w with the same result, all equipment last known good of about a week ago, the board is sitting on cardboard with only the PSU/GPU/CPU/One DIMM installed right now (I am shorting the pins to start it)
Any advice would be greatly appreciated.