Problem with freezing

[aerch]

I have a G3 iBook runing OSX and recently I've encountered an odd problem. My computer will freeze, and what ever is displayed will appear wavy and flicker. I turn off my computer, and when I restart everything happens as normal, but my monitor does not turn on. This began yesterday night, so I decided to leave it alone until today, when it did work. Almost immediately, however, my screen freezes and flickers. Is this a problem with my monitor? If so, how should I go about dealing with it? Any help would be appreciated.