Worms. Can antivirus programs remove worms?..... Are different softwares necessary to remove

Question

Can antivirus programs remove worms?..... Are different softwares necessary to remove spyware,malware,virus,worms etc.....when the antivirus scans and finds a virus but cant destroy it what should be my next step....is there any problem if i use more than one antivirus software....what is the difference between spybot and any other antivirus.....