Sleep Mode Problem

Hello everyone. You can add me to the list of people having problems with the
Sleep Mode in Vista. Sleep mode works if I am connected to a docking station,
and will resume like it should, it doesn't resume under any other
cicumstances. The har disk indicates that activity has started and the lights
indicate the machine is on, but the LCD never recovers. Here are my system
specs and what I have done to date. Let me know if you have a suggestion:

Dell D600
Bios upgraded to Version 13 - Up To Date
1.6 Mobile Pentium
ATI Radeon 9000 -Updated to latest downloads for beta build

Actually updating the bios and the driver for the video card were all that I
could think to do. Anyone else?

Thanks,

John