It has come to my attention recently (and through some internet research) that there is currently a scam going on where someone will call your landline and inform you that your computer has been infected with a virus, and that you need to follow some steps in order to resolve this problem. This is a scam, and could lead to the caller being able to access your data, install programs, and read your confidential information. The scam can also involve the handing over of bank details, since they like to charge for “cleaning up” your machine.
If you receive one of these calls do not in any circumstances follow their instructions. Check that your antivirus is up to date (try AVG free from http://www.download.com for an excellent personal free antivirus suite).