This document is intended to be a primer for new computer users on how to stay safe online. It is NOT intended to take the place of a proper computer training course and/or other instructional materials. If you are new to computers, please take some time and seek out professional assistance -- the rest of the Internet will thank you for it.
That being said, here's some general tips for staying safe online:
Download and install the Firefox web browser and use it exclusively instead of Internet Explorer. IE is chock full of security holes, and new ones are being found all the time. Using IE is a big liability these days.
Do not open any file attachments from strangers. There are a number of worms which spread themselves this way. The same goes for Instant Messages from strangers.
Do not click on links in emails from strangers. There are a number of worms which spread themselves this way. The same goes for Instant Messages from strangers.
Install anti-virus software on your computer, run it regularly, and keep it updated. You can find some products listed here.
Install anti-spyware software on your computer, run it regularly, and keep it updated. You can find some anti-spyware products listed here.
Back up your data regularly. Besides viruses, there are many other things that can that cause loss of your data, such as hardware problems, software bugs, and theft of physical computer equipment. If you are looking for a primer on backup strategies and technology, I have a seperate article on the subject, available here.
This is not a complete guide to staying safe online. But, if you follow the steps outlined above, you'll make it much harder to get any sort of infection, and you'll be doing your civic duty to help keep the Internet free of viruses, worms, and spyware.