I am soooo frustrated - I bought certified refurbished G4 ibook from Apple, had it 5 days and it won't turn on - well it does turn on then flickers off and I get chime and fan but no video - this happens over and over - tried resetting pram, called Apple, they said to bring it to store, I did today, Apple tech looked at it and said it looked fine (it was running fine in the store) but two seconds after I got it started up at home the screen made all sorts of wierd verticle lines and then flickered out and won't start again. any ideas out there?