Some well-known makes of antivirus software have introduced Web-based virus scanning. You can go to one of these Web sites and click the Scan my computer for viruses link. The Web page downloads a small program that will then scan your entire computer for viruses — usually for free (such a deal!).
While there are some drawbacks to this approach, it can be quite useful in some situations. For instance, you could do one of these scans on a computer that doesn’t have antivirus software, or whose antivirus software isn’t working at the moment. It’s also potentially useful to permit a second program (the online scanner in this case) to have a look at your computer to see if your computer is really free of viruses.
Some of the online scanning programs will remove a virus if they detect one, while others can detect but not remove. Depending upon your motivation, you might choose one online scanning tool over another. Or, you could try a different one each time.
Personally, I think that the online scanning tools exist for promotional reasons. When an online scanning tool finds a virus, could easily say something like, “Saaaay, I’ve found a virus here, but you’ll have to buy our antivirus product at full price in order to fix it.” Ka-ching! Sarcasm aside, these online scanning tools have their usefulness.