I upgraded to 10.5.4 on my G4 iMac with a 17" display 2 weeks ago. The other a day a 1 pixel wide magenta stripe showed up, about an inch from the right side. Runs the full length of the screen, cuts through the menu bar. Shows up at start up, so I think it is hardware related. I have owned it for 2 years, am I screwed, or can this be fixed?, warrantied? Thanks for helping.