Install
a good anti-virus and anti-spyware product on your PC, and keep it
up to date WITHOUT FAIL. Mess up here, and your machine will easily
be compromised and your identity stolen. While you're at it, make
sure you keep your operating system up to date with the latest security
patches, and install an electronic "file shredder" and windows history
cleaner such as Webroot's
Window Washer so anything you erase can
never be recovered if you ever sell on your PC.