My PC is a dual boot Win7 64-bit & Ubuntu 10.04 LTS 64-bit. No graphic issues on Ubuntu side. I did a clean install of Windows 7 64-bit (upgrade from XP Home 32-bit), Intel Core2 2.40mhz & 4gb RAM. The graphic card is nVidia 6800GT (256mb) & all drivers are updated. Monitor is 24" Dell & no other monitors on this PC. From the first boot after install, the screen goes black when doing an update or working with multiple windows; only the windows are visible - everything else on the screen is blacked out. If I grab the window & reposition to another area of of the screen, graphics re-appears in areas where the window was moved over. If I do the entire screen, everything restores. I have installed Xara 3D6 which Xara says is compatible with Win7 64-bit but I get odd graphics with it, too. Some of the drop-down menus are impossible to read due to the drop-down having an faded, nearly see-through font graphics that eventually appear but not completely normal. This software frequently locks & crashes the PC. I realize Xara is 32-bit software but Xara say it's compatible. I don't have this issue on the Ubuntu side so this eliminates hardware. That leaves Windows & 64 & drivers for the nVidia 6800GT graphics card. Somewhere there's a clash. How can I trouble shoot this?