I've had a 15 inch pb for 2 years now and Ive recently been having a problem getting it to turn on after I use it for long periods of time. I needed to restart my system and it took me a full hour and a half to get the computer to turn back on. The battery is charged and has been all day. All that happens when I hit the power button is the power on sound plays and I hear the computer making its normal sounds, but the screen does not come back on. What's going on here and what can I do in order to fix it?