Monitor problem or?

Question

my computer broke so i plugged my blcd monitor into my old pc till i could fix it.there was a line vabout 3cm wide of horizontal lines flickering running straight down the center of the screen like a barcode.i cgot my pc fixed and plugged the monitor back into the main pc and the barcode is still there. it makes windows , web pages etc really hard to read. hqave i bust my monitor?