I purchased a refurbished Toshiba Tecra 9100 off of ebay two years ago. When I bought it the battery didn't really hold a charge and so I would always use it plugged into the wall. A couple months ago I had to replace the powercord because it was coming apart... and didnt have any problems with it until a couple days ago when my computer just shut off when I was in the middle of using it. I turned it back on and didnt have a problem after that. The next day it shut off several times in a row and then wouldnt even turn on for long enough to get to the windows screen even though it was plugged into the wall. I thought it was the new cord I bought so I switched back to the old one. I had no problems for a several hours with the old cord until finally it started shutting off for no reason again. I tried the newer cord again and still had the same problem. What could be causing this? Do I need a battery replaced ? or is it some kind of virus? PLEASE HELP! thanks...