Okay mixing things up here folks so lets stop for a moment. AntiVirus software (Norton, McAfee, etc.) are used like Doctors to protect you from viruses, and include most of the time thier own Firewall included. It is not really needed for your home computer as the software firewall is the worse defense as compared to the built in firewall (hardware) built into the router you should have.
AntiMalware is to stop the Advert/Social Engineering junk that tries to convince you (like a Salesman or Telephone Solicitor) you need to 'buy' a program to clean your PC, your PC has a virus and only thier program can remove it, etc. Malware by it's nature really doesn't 'damage' a computer (rending a hundred advert pop up windows is not the samething as replace every word in your documents with the word COOKIE! though both may make your computer useless), so AntiVirus normally can't "stop" malware as it doesn't see anything 'destructive' happening (remember they are just trying to convince you there is a problem when there isn't).
That said, if your at home, have a router you don't need it. No AntiMalware will 'fix' a firewall, and as I said, may already be running in your copy of Norton/McAfee/etc.
To add to what Tom is saying... Malware is the broad term used to cover all forms of unwanted software. This includes viruses (simply software that you don't want, or does something unexpected), Trojans (simply viruses that activate on a delay, usually by opening a specific program or on a timed interval), spyware (exactly how it sounds, it watches what you do and acts accordingly. Usually to try to sell you something), Rogues (Software that trys to act like it something else, to get you to pay for either a non existing service or a unwanted service), and so on...
Because these can be so ridiculously complicated sometimes, not to include software that runs without you even seeing it, its best to just do a clean install and work from the ground up.