I've had my G4 Powerbook for two years and two times in the past 6 months have experienced my screen "freak out" - whereas everything sort of scrambles and appears to have "interference" like a television would (only without the snow) almost like a TV when the antenna needs adjusting. Anyway when I re-booted it would be fine. Now today I'm getting very slight shimmers periodically flashing across the screen (I'd say once every 15-20 mins) I feel it's on the verge of something very BAD but I'm hoping it's a loose connection or ???....any body ever have this happen? Know what the problem could be?