IMHO, it doesn't sound like a driver problem. It sounds like a gassy tube.
Picture tubes in monitors (and televisions) can have a couple of things go wrong with them, that will adversely affect quality and brightness.
The electron guns can get a little oxidation on them, so they do not emit electrons as well as they should....
The tube can get "gassy", where there is gaseous obstructions in the tube, obstructing the flow of electrons.
My advice, if you want to keep the monitor, is to take it to a TV repair shop, and have them test the tube, and adjust the beta voltage.
DO NOT ATTEMPT TO DO THIS BY YOURSELF. There are KILLER voltages inside of any CRT-based monitor or television set. I'm not talking "Oh, it runs on 110 volts", I'm talking upwards of 35,000 volts. NEVER attempt to work on a television or monitor if you don't know what you're doing!
Just my $0.02
"In order to start solving a problem, one must first identify its owner." --Me
--Greg