I've got a DELL OptiPlex 320 with a PCI dual graphic card (Diamond S9250 PCI 256 DDR). I recently preformed some Windows updates and when the computer restarted, the system was using the generic Windows display driver where the desktop is that lovely turquoise color and all the graphics are huge. I then reinstalled the graphic card driver and everything looks fine. Except for the fact that this user uses both his monitors vertically or portrait.
When I go into the advanced display options (Catalyst Control Center) I get the choice to change the rotation Left 90 degrees. When I choose that, I see the monitor icons switch to portrait mode, but when I press OK or Force, the monitor icons switch back to landscape mode and the rotation goes back to Standard Landscape. The actual resolution of the monitor never changes.
I've got another DELL machine, different model, with the same graphics card. Everything seems to be working there fine. The driver versions appear to be the same on both computers.