How Anti virus work? And which is the best antivirus.?

Anti-virus (AV) packages look for known patterns in files that may represent dangerous code within a file. These signatures or patterns are continually expanding as new viruses emerge, and the AV companies issue new signature file updates typically several times a day.

Some AVs use heuristic analysis to spot variants of a virus before the AV company characterises it and issues a signature update.

AVs are a balancing act to be sufficiently sensitive to stop infections, but not over-sensitive and triggering falsely on files that are actually clean. Most AVs allow for known clean files that cause false alarms to be marked as safe. Some years ago a normal .txt file I had created was picked out during a routine AV scan.

Some AVs will scan the contents of ZIP files and other forms of compressed file.

Some AVs look for known risky web sites and either warn about the sites or even block access. Some Internet browsers also block dubious sites.

Generally you get what you pay for. Free AVs are good for general browsing, but many of the paid-for AVs offer more complete protection.

You should read the various reviews and specifications and check prices and decide what level of protection you need.

I don't know how they work. Avast is the one I use.

avast antivirus is best and Avast Antivirus provides a range of scans to protect your PC from malware. A comprehensive scan that detects malware, out-of-date software, browser add-ons with poor reputations, network threats, and much more. also using it..

The few times I have fooled around with windows on my puters- I found both Avast and AVG to work well enough.
But I have mainly used Ubuntu or Linux Mint since 2008 and just do not have issues.

I have used all of the better ones and now just use AVG. And they update it several times a day and when any new virus comes out they are on it immediately. Also their tech support is by far the best I have found as most of them don't care about being bothered if you have a problem.

Ron

Anti viruses use what's called definitions...definitions are a list of known virus...you keep the definitions updated by downloading them (automatically or manually) your antivirus looks at the list of know viruses and if it sees a match it blocks it or puts it in quarantine so it cant infect your pc...BUT...when a new virus comes out it wont be in the definition list because its new and the virus company needs to find out what it is and then add it to definitions to stop it...so you may already have the virus before the definitions are updated...is there a good antivirus?...NO...I find them more intrusive than a hacker because you give it total access to your pc...not to mention ads from h3ll from third parties that also have your info...and you agree for this to happen...I been using pc's for decades and used all the antiviruses pay and free and do you know how many virus they caught? ZERO...