What does an anti-virus do?

Keeps dangerous things from invading your computer and gets rid of them if they do get in. Some people are mean and write programs that will ruin other peoples' computers. Then they find a way to sneak it into your computer when you download something. Anti-virus is important if you are connected to a network, like the internet.

What does an anti-virus do?anti virus protection

It tries to eliminate computer viruses that are on or trying to get on your computer. Some viruses can't be deleted. Spyware is different. It stops and destroys spyware that is on your system.

What does an anti-virus do?antivirus

I helps to keep your computer free of virus that canslow it down or even erase programs. Get a bad enough virus, you may end-up having to buy a new computer. For anti-virus to work properly/efficiently it must be updated regularly. Also do a full system virus scan on your computer at least once a week.
anti-virus his best work to weak virus and try to terminate it like antibiotics

antivirus medicatioin adminstrate to patients to help them to fight aganist virus
Monitors your computer and all data coming into it. If it spots a file that has a virus it either deletes it or quarantines it so it can't cause you problems. It periodicaly scans your entire system and hard drive for active infections.
it helps you detect viruses
An anti-virus is pretty self explanitory. It counter-acts a virus.
it helps to fight againts viruses. Viruses are potentally unwanted softwares(in simple words) that harms the comp.

An anti virus fights agains such softwares.
Well looks like everyone has pretty much answered your question....simply it keeps and eye out on incomine traffic and hunts for viruses and detects any existing viruses...with the right software you can remove the harmful viruses from your computer...a good anti virus thats also free is AVG..I swear by it..in fact I have a brand new computer that came with McAfee..and I will be REMOVING that one (ugh) and installing AVG today.