evga 8800GTX picture problems in portrait mode?

I just upgraded my vid card from a xfx7950Gx2 to a evga 8800gtx. While I had the 7950, there is no problem with gw running 1200x1920 in portrait mode. However, with the 8800gtx and the latest driver, the monitor just flashes between gw and the desktop. The gw frame doesn't even fill the length of the monitor (1920). I tried to disable all quality enchancement settings (AA, etc), in gw as well as nvidia control panel, but nothing seems to help.

Right now, I am resort to running in landscape mode (1920x1200). There is no problem with gw at all. Anyone experience or heard of similar problems?

get driver cleaner, Download the latest nVidia Drivers,
use drivercleaner, and Clean your old drivers off totally...

install the new drivers, then get the December 06 DirectX and install that AFTER

then start guild wars, you shouldnt have a problem..

Thank you for the reply. I tried reinstalling the drivers and dx 9c after following drivercleaner's instructions (disable network card, boot to safe mode, uninstall existing driver, run drivercleaner, reboot, etc). But the same problem still there.

Thank you for the suggestion though...!

Sounds like a bug in nVidia's current drivers. You likely can't do anything until they fix it. Have you asked on http://forums.nvidia.com/ or tried contacting nVidia's tech support?