Seeing if the graphics device is set up correctly in the BIOS (I am presuming that this onboard graphics?) If this IS an onboard graphics device, it will probably "share" memory from RAM - what is this set at?
If you have the choice, setting the monitor to Plug and play.
You could also try removing the Graphics drivers from Windows and before reinstalling them, use a Windows generic driver for VGA. Then reinstall the original drivers from the motherboard drivers CD. - What chipset does this particular board use? If it's VIA, it might help to download the most recent VIA 4 in 1 drivers.
The CTX monitors are pretty good and so wouldn't be looking too closely at that - although it is something to bear in mind for the future.
It might be worth your while purchasing a Graphics expansion card - but presumably, because you have onboard Graphics, you will not have a AGP slot and will have to resort to a PCI Graphics card.
Anyway, check the BIOS, remove the current drivers and reinstall, and try and use the Plug and play monitor.
Hope this helps a little.