Spyware, Trojans and worms. These are different forms of software that have one common intent. They want to infect your PC or server. You can't be too cautious when dealing with any form of malware, so the following list is a few reminders to help protect against these threats.
Reminder 1: Make sure to have a reputable anti-virus software product installed on each PC. Norton and McAfee are both good products. Also make sure to keep the virus software updated. A good anti-virus software product will constantly update the list of viruses it detects and protects against.
Reminder 2: Never open zip files unless you know who the file is from and are expecting it. Double and triple check the legitimacy before opening any zip file.
Reminder 3: Always be suspicious of any email you are not expecting or don’t recognize. It may be tempting to open that email from the guy in China who wants to place a big order with you, but the probability is that his intentions are not good.
Reminder 4: When in doubt, look at the email address. If the senders email address ends in something other than .com and you don't recognize the sender, then it's probably best not to open the attachment.
Final Reminder: Be cautious.