Post an "lspci" output here. I'm guessing that it's as simple as you no
using a recent verson of X (the Debian Woody release version is rather
outdated) and hence the video driver that should work, isnt.
Change the driver in your XConfig file (/etc/X11/XF86Config-4) file to
"vesa" and see how that goes. Provided you have a semi-ok motherboard,
then you should at least get software rendered graphics, and hence a
useable X session.
We really need to know what the Onboard video is - lspci should give us