As of yesterday there has been an updated driver for the Optiplex 170L systems published via Windows automatic updates.  DO NOT INSTALL THIS DRIVER as it will leave your video display in shambles!!  The adapter is the Intel 82865G integrated graphics controller.

 

The only way to fix the issue is to roll back the driver to it's original or to completely reinstall the driver located on the Optiplex resource CD that came from the manufacturer.  I hope this helps!