For some reason the monitor is not getting all the color signals. You can try unhooking the monitor cable from the back of the computer and reseating it to make sure it is properly connected. If this does not work then the cable is going out or the firing guns on the CRT are going out. If it's the firing guns, it would be cheaper to just replace the monitor because the CRT is 80% of the cost of the monitor HTH
.

__________________
~Rae

Avatar Credits: Chickie by Hunibuni, BG: Felina-Iron Orchid, Border: Days of Eden-Valerie Fowler