Locked out of vista because of a virus

Hello,
my name is isaac i have o pc running vista and i have mcafee.i recently tried to restart my pc and found my self locked out .After i login my privacy center pops up and starts doin a scan that takes about 7 mins. Shows a quite bit of detected viruses then askes if I want to fix and clean em .As i click yes it says that all my sofware is out of date and i needs to insatall updates for them.When i select update it says i have to pay...do i have to pay just get back to my desktop that dont sound right ..................so if anybody knows what im talking about please contact me.