If you were attached to a network, remove every machine attached to the network, boot from a clean disk, and scan for viruses. Finally, you will need to scan your network server. But if you don't eliminate a virus right away, your system could be damaged. There are a lot of rumors about viruses. Here's a run-down of rumors vs. truth.
Viruses are programs.
Unless you do something that runs a virus program on your computer you won't get one. They don't swim upstream in the telephone lines toward your computer. You could get a nasty surprise this way. That's why I don't use an HTML capable e-mail system. A Web page can damage your computer.