Acer Aspire 3820t displaying blue screen on booting

Hey, I got this laptop a day back. It was displaying blue screen on booting then finally displays at login window with windows 8 on. It could display blue whenever you tried using special function like f2, f8, f12 at start up. So I resumed to using an external monitor which was fine. I installed windows xp instead. But now my most worry is that now it's black, but displays with external could it require screen replacement. Would welcome all ideas. Thank you