I've been accessing my headless G5 through my Mac Mini's screen using screen sharing as they're both hardwired to my router. After a huge fan whirring event while I was on the phone with Apple support trying to resolve a completely unrelated problem on my Mini, the G5 is no longer behaving normally. When I start it up, I get the totally normal blue login screen and am able to do so, but then it gives me this smear of white/black/other lines beneath which I can barely see the menus and it's impossible to use the computer. What's going on? Why is the login screen normal? How do I resolve this?