Sounds like you may have lost a component but keep trying.
Does it behave the same way connected to another computer?
No refrigerator magnets nearby, right?
Is your power okay? Your mention of your bf's monitor says you have interference or a power problem. Try plugging it into another circuit. (not just another outlet) You may have something on the line that's interfering. (refrigerator, air conditioner, etc.)
Before giving up, physically move it elsewhere with a different orientation and make sure the problem remains. CRT's are very sensitive to magnetic fields.