If an offer seems too good to be true, it is
Frequently e-mail offers hide viruses, don’t just assume that an offer is legitimate if it shows up in your e-mail inbox. If you see a link in a suspicious e-mail message, don’t click on it unless you are sure it is legitimate. The link may look real, but be careful, the link might contain hidden files that can cause problems with your computer and data.
Know where your files come from
Don’t open anything you don’t trust completely. A virus can do nothing unless you actually run the program that it is attached to. That means that simply downloading a file does not put you in any real danger. If you decide after downloading that you don’t exactly trust the file, avoid opening it or delete it until you can confirm its integrity.
Don’t download attachments from a source you DO know unless you were expecting it.
Many times viruses can mirror a trusted e-mail address without the address owner’s knowledge. This means you can receive an e-mail from a trusted source but the e-mail contents are not trustworthy. If the writing is odd or the attachment looks off, do not click it. Verify with the e-mail sender that they intended to send you the attachment you received.