video card problem

hello folks out there im having a problem with my ge force 7800 gs vid card when im simming, the card as it seems works real good until i try to undock and put to another screen, im running a nine monitor set up, five for views and four for instrumentation, im flying the level-d 767 and when i try to undock and move to another screen it locks up.what i will do put the main screen into windowed mode and then undock and move what i need to another screen then save it, and i will then go back to full mode and then everything locks up and if you wait a few moments both monitors will go into a video fail and the screen will be in 8 bit mode, i then will have to restart and everything is back to normal, im sure it is a video problem because it does not matter which plane i use. i have all of the updates FS9 9.1 and so forth.my vid card has the latest drivers 84.43 from the nvidia web sight.so what may i be doing wrong......Thanks............Robert