What protects a computer against viruses by identifying and removing any computer viruses found in memoryon storage media or on incoming files?

Antivirus software protect computers from viruses and other general malware. There are two types of antivirus programs: manual and real-time. Manual antivirus programs have to be executed by the user in order to scan the computer. Real-time antivirus programs are of better use and provide more security due to the fact that they continously scan programs, memory in the RAM and any other programs that the user might execute during the time that it is active without having to be executed by the user.

Antivirus programs use a specific algorithm called heuristics. When an antivirus program scans a computer, it checks the code or text in a file and then cross-matches the code with known viruses in a database. If an antivirus finds a match or a potential match, it flags that file as a virus/potential threat and notifies the user of the results.

Antivirus software only protect the user from self-replicating programs like viruses or worms and do not remove Trojans, rootkits, spyware, keyloggers, etc (although newer antivirus programs now detect almost any threat).

Get a good quality antivirus program like Norton 360, McAfee Antivirus Plus, or Comodo. Now get an anti-spyware program like Spyware Blaster or SpyBot: Search and Destroy. For further protection, get an anti-malware program like MalwareBytes.