I don't know... It could be a monitor problem, but it also could be the video card. Its hard to tell which one has the problem without having a spare of one of them. If you have a spare monitor, that is usually the easiest thing to check, as you do not need to uninstall drivers, set windows to a generic vga card, remove the video card, install the new video card and install the drivers. The monitor is just a simple wire swap (after moving the monitor next to the computer)...
So, that is a good place to start. Swap out the monitor and see if you are still having the same problems you reported. If you are, then its a good bet the problem is your video card, if it is solved, then it was your monitor.