You might also have a cold solder joint that's arcing.
I know in some Trinitron computer monitors they like to have extra static discharge internally that sometimes affects the screen, but I think I read that was due to the design of the Trinitron's and chassis, especially once the patent ran out and others (besides Sony) started copying it.
In any case, if you don't know anything about monitors you shouldn't be messing with them until you read up on them, and basic electronic knowledge. Find someone qualified to look at it. Monitors can kill or maim (no pun intended), even when off if you start poking around them without knowing what you're doing, so it's best to either learn everything first, or find someone who can help you.
Safety about monitors has been written numerous times here so you can start here, or google for web pages that talk about safe handling of monitors and repair too.