I just recently upgraded my sony vaio laptop pcg-934A with windows xp and installed a wireless wlan1500 pc card. Before installing/upgrading, my battery was working fine, up to 2 hours of watching a DVD movie on it. Now, while the battery shows as 100% charged, whenever I disconnect the power cord from the laptop, the battery power instantly shows up as 10% charged within seconds and automatically shuts off. I have to replug the power cord onto the laptop in order to have power. Is it possible that the battery went bad overnight? I have been trying to figure this out for a week now and am nervous about taking the laptop to a repair shop, only to charge me $100 just to tell me to buy another $100 battery.