Whenever you are downloading programs on the Internet from a distant system to your own computer, there is a possibility that you may encounter a computer virus. The chance is remote if you are downloading from an established software repository, but more likely when downloading from an obscure private or foreign site. The virus might be contained within the software or attached to a data file, such as a word processing document. Usually these are mere annoyances, and cause no real damage to your files. Occasionally, you will encounter a virus that has the potential to cause more serious problems.
All of these can be taken care of by downloading and using an Anti-Virus Scanner. An Anti-Virus Scanner is software that will search through your files, looking for a virus from a long list of those that are already known, or looking for evidence that a virus is present that may not have been previously encountered. You can protect yourself from these by visiting C|Net's Download.com site, clicking the utility category and examining the Anti-Virus section to select and download an Anti-Virus Scanner.