Monitor

unit powers up ok,steady green light, when the computer is started monitor display blinks on and off (but no detail) as xp loads as expected, once loaded the monitor displays a green screen (desktop colours) the screen is divided into 4 equal horizontal bands, getting darker towards the top,with no video detail although there is some activity on the screen but only a few white horizontal lines about 1 pixel wide changing position on the screen.
The display did burst into life at switch on at one point but only the once