If you received and opened the virus email, your address book may well be the next one used to distribute it, from your computer. These things can be malicious.
I recommend SpyBot and MalwareBytes, two freebies that can keep you out of trouble. Install the SpyBot resident called Tea Timer, which will watch your registry and intercept attempts to install software on your computer. It warns and gets your permission, constructs a "white list" for valid stuff.
A weak spot on any Windows computer is the Internet Explorer itself, it has some special software "objects" that are particularly vulnerable to hiding these critters. Again, Tea Timer can help keep you out of trouble plus it is best to keep your Windows software updated, a continuous process (!).
I use Firefox and recommend it over IE as a primary browser. I'm sure others can recommend other preferred alternates. Of course, you cannot uninstall IE as it is at the heart of the Windows desktop and user interface.
Once you get things cleaned, try deleting all your cookies, then go and visit ONLY your regular sites to reload just those cookies. Then set the browser to allow cookies, but discard them when you close the browser. Also, install Firefox add-ons NoScript and Adblock Plus.
Good luck on getting rid of your virus. SpyBot may find a worm or trojan your main firewall (say Norton) didn't catch and doesn't get rid of. If you can't get SpyBot to successfully fix it, contact Safer Networking (SpyBot's creator), read their procedures then get help. It may take a few days to fix it, but it you follow their instructions, there's a good chance of killing it. (Ask me how I know all this, and why I donated money to Safer Networking after they rescued me..)
L.
"You can lead a horse to water, but if you can get him to float on his back, you've got something." -Hartley's First Law