problem with X in a laptop

[jcazor at ya.com]

hi,

im having problems configuring the X window system in a IBM 
thinkpad laptop.
The servers starts ok, but the problem is that it doesnt fit the 
full screen. i dont know if you undrestand me, because my 
english is not very good.
im gonna explain it with a picture:

         |-------------------- |  <=3D  screen of my laptop
         |   |---------------|  |
         |   |                     |  |
         |   |                     <=3D=3D size of the X's screen
         |   |---------------|  |
         |---------------------|


the video card is a silicon motion, but the driver doesnt work, 
so i used a generic VGA.
Now im using FreeBSD 5.3 with Xorg, but before i was using 
debian with XF86 and i had the same problem, but i fixed it 
startingthe X server with the "-dpi 100" but this now doesnt 
work.
i also have used the xvfb server, but with this server doesnt 
work.

any idea is welcome.
thanks in advance.

jcazor.