after installing Sarge ; X could not start because of some mouse related problem
and i had that message saying that due to a mouse problem X will not start ; and that gdm will be diabled for the moment

as i was searching for a solution i installed gpm that activated the mouse in terminals
and added a couple of lines in XF86Config-4 in the section of the mouse
when i restarted the PC
i saw that X has initialized fine BUT at that moment when gdmlogin was appearing ; a short beep is heard and evry thing
just freezes
no keyboard activity [even numlock ]; no mouse activity and no display actvity [the cursor in gdmlogin textbox does not
blink]
when i try to SSh throgh the network i can login
but nothing interresting in the logs of gdm or XFree86.log
it just ends with
================
Warning: font renderer for ".pcf" already registered at priority 0
Warning: font renderer for ".pcf.Z" already registered at priority 0
Warning: font renderer for ".pcf.gz" already registered at priority 0
Warning: font renderer for ".snf" already registered at priority 0
Warning: font renderer for ".snf.Z" already registered at priority 0
Warning: font renderer for ".snf.gz" already registered at priority 0
Warning: font renderer for ".bdf" already registered at priority 0
Warning: font renderer for ".bdf.Z" already registered at priority 0
Warning: font renderer for ".bdf.gz" already registered at priority 0
Warning: font renderer for ".pmf" already registered at priority 0
===============

now i can find no clue on how to debug this or how to pursue in a certain direction toward solution

Login as root and try this:Answer the questions or accept defaults if unsure.

Dear All
Please congratulate me
i found the root cause
Just changed this
Driver "sis"
to
Driver "vesa"
and now Xwindows works gr8
off-course i am loosing much of the feature of my Booming SIS chipset ; but untill i have a good understanding of this
http://www.winischhofer.net/linuxsisvga.shtml
i ll settle for Vesa driver

many thanks to all