Security doesn't have to be expensive. Many useful utilities that help prevent or rid your system of viruses and spyware are free. Here are a few favorites.
Trend Micro's Housecall is an excellent online virus scanner for a quick and easy check. Though it's not a replacement for installed antivirus, it makes a good second opinion scanner.
Even dial-up users need a firewall. If you don't have one, get one. ZoneAlarm is free for personal use. ZoneAlarm monitors everything going in or out of your computer, preventing intrusions from hackers and rendering remote access Trojans impotent - assuming its properly used, of course.
Think the firewall you have now is protecting your system? Make sure it is. Test it free, compliments of GRC.com.
There are so many possible attack vectors, it can be hard for even experienced users to keep a close eye on their system. Thankfully, there's a friendly little Scottish terrier to do it for you. WinPatrol's Scotty barks when suspect changes occur, giving you the option of investigating further, denying or allowing the changes. It also locks down your HOSTS file, preventing surreptitious Internet redirections that can hamper your security.
Let Microsoft scan your system and tell you of any missing security patches that might leave you vulnerable to viruses and hackers. Be sure to download and install any Critical Updates listed.