hi everybody, I am using an old AMD system (since 2002) and it had few misc upgrades (ram, hd, graphic cards, psu etc) over the years. it was working fine with all the upgrades as well. the past few months, i started to leave the pc with internet connection on for days and 2 weeks ago when i returned home, the pc was off after 4 days of continous activities. I tried to power up but there was no response. i switched off the power switch and turned it back on, it powered up for few seconds and shut off again. on 1 occassion, i thought i smelled some burnt smell coming out from the system but i was unable to determine from which part. i read numerous forums and concluded that the prob lies with the psu. i bought a new psu, it boot up all the way to window and it shut down by itself again and since then, its the same prob again with the new psu. so now i am doubtful whether its the psu issue. i read somewhere it could be possible virus and there are AV for those but the qn is how do i use AV when i can't even boot up? beside this, what else could be the prob? appreciate whatever advice you may have! thks!