Hey I just got a new laptop and Im looking for a really good free antivirus + firewall, any suggestions?

Johan

Hey i need to download a proper antivirus or sumthing .. sum1 used my pc n i got sum kinda virus, which i cant get rid of! my norton has expired
Keeps giving me system alerts.. i dunno what to do !! plz plz plz tell me if i can download anything to detect it for free i can delete them manually !!
thnx ppl !

Gianna