Re: AMD64, Tyan K8W, Geforce 5700 = black screen
drumz, have you tried to switch the graphics cards in the computers or the hard disks ?
I had a similar problem that was fixed by replacing the motherboard, I've a new K8W that worked ok with my 5700 Ultra, that was later replaced by a 6800 running perfectly.
My previous MB only allowed me to use AGP 4x, with the replacement board everything runs fine in AGP 8x.
Your hardware may be broken. If you need more info, please ask.