Did you say earlier that it is an ATI graphics card? Is it a laptop? Have you done the stuff at
http://apps.pirates.go.com/pirates/v...s_drivers.html to upgrade drivers? (That helped my game's performance significantly in the past.)
Start --> Settings --> Control Panel --> Display --> Settings (tab) --> Advanced --> Displays (tab)
or something similar to that, should be where you set your monitor to work in default mode, instead of for multiple displays.