do you have a video card in the computer ?
if you are running it from the onboard video I suggest you go to the motherboard manuf website and get the latest drivers for the motherboard.
this may not help you in the end and you may need to put a video card into the machine - though your machine may not really have enough power to take advantage of the 22" at its native resolution. and a 5 year old motherboard will be AGP graphics card slot , or even PCI.
can you give us some more details of your system .
Motherboard manuf and model
ram
cpu