well.. u said u had symantec.. so your computer is probably crawling with worms and viruses as i sadi.. symantec doesnt block crap or catch barely anything
there have been some serious problems that i have heard of with norton. for example my dad (bigger tech-geek than me, i am not worthy in his presence ) had norton remove a program that was in his exceptions list :|. he contacted symantec and received no response. im thinking damage to the filesytem i.e. the FAT