Windows Manager is too Big

["stumpy@capital.net" <stumpy@capital.net>]

Howdy Linux Gurus,

My windows manager is too big for my screen.  I have to move the mouse
down to the bottom of the screen to have it "float" up.  I'm using
fvwm95.  I checked the man pages and it says something about using the
command DeskTopSize, but when i try to use it it says command not found.
I think the problem is more of an X problem then the actual windows
manager.  When I configured the system I used xfconfig (? the
un-graphical one) and I had it search for the possible display types. 
It seems that the only usable display it found was 640X480.  My other
computer that is running M$ Win 95 is set to that and it is fine (I'm
sure this is does not mean anything on the Linux platform).  So any
step-by-step instructions would be great on how to fix this problem.
Thanks.

Tom