There has been more than one company's computer crew who pulled all-nighters eliminating viruses that threatened the entire network.
Companies spend thousands of dollars protecting their networks.
If it's not from someone you know, be extra wary. If there is an attachment or Web link to open, sound the alarm bells. If it has an extension like .vbs or .exe, don't touch it. Those extensions ignite programs that can use the file to destroy your machine. These tips are not foolproof.