Expertise Needed

I'm hoping for an answer from someone who knows a lot about CRTs.

I have a Viewsonic A90f. I bought it in 2003. Over the years I've developed a few problems with it, and I'm trying to figure out what's causing them.

The most important is the most recent problem I've been having: flickering horizontal lines at the bottom of the screen. The flickering ranges from half an inch to two to three inches high. When I hit the sides of the monitor, they go away, but sometimes only momentarily. The flickering comes and goes completely at random, stopping for as little as a few seconds or as long as several hours.

Another problem I've had with the monitor is a faint but high pitched squeal that comes out of it when it's plugged into an active power source and turned off. I have to plug the thing into a power strip and switch off the power strip in order to keep it from making the noise. It's barely audible, but just loud enough to notice.

Lastly, and least important is the fact that the OSD lock option is always on by default. When I turn the lock off, it only stays off as long as the monitor is turned on. If I switch it off and then turn it back on, the lock is reset.

I really don't want to shell out the money for a new monitor, and though CRTs are superior in every way to LCDs, they are becoming increasingly hard to find... and not any less expensive.