I started having this problem about 4 days ago. I run my laptop with its power cord in all the time...wasn't doing anything and it had some stuff like AIM and word running and then just shut off. I'd HAD problems with the AC power jack coming off of the motherboard before so I assumed it was a battery thing, but I hadn't gotten a battery warning. Wouldn't turn on...acted like it wasn't getting power even though the power CORD was lit up. Took it in...of course, powered up for them and they found nothing wrong. Has happened a few more times since then. Will just randomly shut off and then not turn back on. Sometimes for a few minutes, sometimes hours. Can I rule out viruses and anything software related since it acts like it isn't getting any power when it is off and plugged in? (light should be blinking) Any ideas of what the problem could be? Hard to diagnose when the thing acts just fine at the repair place!