I had this virus about a week ago and it had infected over 200+ and nothing works now, so i try to reformat my computer (acer aspire M1640) but then i realize that its preinstalled and i have NO idea how to reformat preinstalled vista home premium so i was hoping someone can help me and go with me step by step trying to recover my computer, so please some one take there time and show me step by step what i should do, so i can reformat my preinstalled vista home premium. thank you and by the way the computer did not come with a back up disk so i didn't know and i did not back up my files..