[Steve]

Its always difficult to tell for sure just from descriptions of faults but I would now say that you are probably at the point of needing a new monitor. If possible I would ask around your friends and relatives to see if any of them have an old one that is not used much and if they would be willing to lend it to you for a couple of days so that you can test.

You'll then know whether its the monitor for sure and if so, be able to make a decision to replace it knowing that there is no chance of it being good.