guys, im having a strange problem with my pc. my pc is usually on for almost 12-13 hours a day. two days ago, in the night at around 11pm i was surfing some sites in opera and all of a sudden, a popup window appeared. i closed it but suddenly, my pc shut down. after that, i tried to turn on my pc but no use. Even bios screen didn't start. the processor fan rotated 2-3 times and the pc shut down again. i was tired at that time so i slept. next day, my pc started fine, i worked on it all day. but in the night, at around same time,11pm, it turned shut down again automatically!!! i tried my best to revive it but no use. i disconnected my hard drive (i thought, it may be some virus) and tried to boot from dvd-rom. but no use. as earlier, even bios didn't start. now, next day, that is today, it has started just fine. so im posting this. guys, if u have any idea, plz help. i haven't checked with my antivirus yet, but im goin to do it now. hope to see some response from u!!