Refresh issues with Nvidia GeForce 8400GS Grahics Cards

[Anonymous]

We have two new computers with Gigabyte MB, Intel Duo E7400 CPU, 4GB RAM, Nvidia GeForce 8400GS graphics cards all running on windows XP (32).
Both machines are having the same problem, silhouettes of dialogue boxes remaining on the screen after you have clicked OK. Then not being able view that part of the screen or work thru it again unless you flip out of Archicad and then back in. It seems to be a refresh problem.
We have downloaded the latest drivers and tweaked some settings on the driver however the problem still remains.
We have a third machine with the same specs, but with a different mother board and it has NO problems.
Can you please help as it is very frustrating?
Many Thanks

[Halixman]

Try OPTIONS>WORKING ENVIRONMENT>ADVANCED REDRAW OPTIONS

My set is:

Model display: Full model (by default is set to simpified).
2d antialiasing: UNCHECKED (by default is unchecked. That's ok to me because is too blurry).
2d drawing hardware acceleration level: FULL (by default is set to 3)
Memory usage: HIGH (by default is set to high)

My pc specs:
Core2duo e6400 2.13 GHz
Ram 4GB
video card Asus EN8800 GTS 512MB.
Windows 7 64 bits
I solved today a lot of redraw problems with this settings. Try your own settings. Good luck.