if you have any time to download and install something before the shutdown get this software called trojan remover linkright here downlaod and install, its shareware so after 30 days you have to pay for it but you have 30 days! so install then after just run a scan i am 99% sure it will find the virus and delete it.I use this software myself i have the full version and i have also had viruses, alot of my friends come to me to help them with viruses and i use this, everytime it gets rid of it. try also click start, click run, type in msconfig and then click the startup tab more then likely the virus is in there so uncheck anything that looks odd or that you cant recongize and reboot. usually reformating is not needed. good luck