Nvidia 9600GT Font Rendering Looks Terrible

I just upgraded the video card on my PC from an ATI X1600 series to a
Nvidia 9600GT series card. First I uninstalled the ATI Control Center
and drivers as to their instructions. I then shut down the machine and
changed cards. And then I installed the Nvidia drivers. Everything
works fine except one thing. When I crank up the resolution on my
Viewsonic 23 inch flat panel to 1290*1200 the font rendering looks
terrible. Characters and words are almost impossible to read. When I
turn the resolution back to 1600*1200 like it is now, things look a lot
better. Is there anything I can do to restore the higher resolution?
In some ways this video card is more compatible with my monitor than the
ATI. For one thing, the DVI-D mode works just fine.

Thanks