I recently purchased a new system (see specs below). I intially tried to run 1680x1050 but found that my monitor would not support a high enough refresh rate to stop the black flickering. I therefore turned it down to 1440x900 which gets much less flicker and get run at 75hz. However at this resolution I get green flashing dots along certain objects on the Desktop and in games. The dots are grouped, each is a pixel and it usually occurs on light green/yellow coloured objects.
I have updated my drivers, my GPU is running at a cool temp and they are not dead pixels.
Vista Home 64 Nvida GTX 285 1G 8 Gig Ram i7 920 CPU 22 Inch Monitor
Is this a CRT or flat panel? Either way: Check the cables are the correct type and fully connected and take a look at the Nvidia control panel and check your display is correctly configured in the drivers.