(Kach - your inbox is full)
Here's the various PC stuff I use - had great luck with it, and it's free.
http://www.rennlight.com/prog/
The most important thing is to distrust everything. Don't click on that tempting attachment from your Aunt Edith unless you're absolutely sure you know what it is.
Install this stuff, or PayWay equivalents, disable file extension hiding, don't use IE for your browser, don't use Outlook for email, and you're 3/4-way there.