It might not be graphics related. Missing a mouse can stop X-windows from starting. What happens if you press ctl-alt-backspace? Does it kick it back to shell where you started X? My computer would hang - couldn't do anything.
What graphics card do you have in the computer? Is it an SiS? If so, then check http://www.winischhofer.net/linuxsisvga.shtml
to see if those drivers cover your card. The site is pretty professional; you can probably skip reading most of the text and just head to Download, and then Installation instructions. Just need to know your XFree86 version and your gcc version to determine what binary to download (or worst case, compile your own from the source).
If for some strange reason you don't know what your graphics card is, then I believe that in /etc/X11 there is an XF86Config for a vesa frame buffer (think it is called XF86Config-vesa) - that might be generic enough to work. Also check the hsync and vsync for your monitor.
Finally, if you want to get a XF86Config working, but xf86cfg won't work because of your display issues, try
It brings up a text-based version of xf86cfg that will let you set your monitor, graphics, card, mouse, keyboard, etc.
Hope that helps.