If your computer begins to do things out of the ordinary, or if it stops being able to do things it has always done in the past, it may be infected with a virus . It is important, though, to distinguish between virus symptoms and those that come from corrupted system files, which can look very similar. Remain calm and objective, and rule out more standard causes before suspecting a virus. Prevention is a matter of vigilance and avoiding contact with unknown disks. It is usually the unwary who get computer viruses.
Most antivirus packages contain routines that can perform each kind of task.
One good virus protection software package is Norton AntiVirus for PC-compatible and Mac OS computers. Back up your files. Viruses are one more very good reason to always back up your files. Check your backup files with virus scanning software before using them. This will prevent the virus from spreading to your original disks.