Good to hear.
I'd like to recommend some prevention tactics.
Malware usually installs because of (1) User action: Clicking on the wrong (or a misnamed/deceptive) link, or installing software not from the authors' site, or installing pirated software; (2) Out of date vulnerable software installed, including out of date Windows, an insecure browser with permissions set a bit loose for today's environment; and the misfortune of happening across something in this state that the AV doesn't detect/can't stop. (All the AV's will miss the occasional one. So it doesn't necessarily mean "change AV's".)
User interaction is up to the user.
Up to date software can be helped a lot by visiting
Secunia, mouse over "products", and perform an online scan. (As a result of the scan, you may want to install the PSI. It's free.) The scan will measure the status/known vulnerabilities of a lot of the software installed. Such things as Flash players, Java, Adobe etc. A lot of the 3rd party stuff that ends up installed. It will also offer the "how to" on what to do about it.
Known bad sites can be blocked by using a hosts file, which prevents the machine connecting. It can also block a lot of the unwanted content of a page, like some ads. An example of one (with instructions) is
Here. (I use the Hostman app - linked within- to manage/update it. Easy as.)
If you don't have a two way software firewall, I'd get one. Online Armour, by Tall Emu, Outpost, PCTools, and Comodo all have free versions that are effective, particularly if you are also behind a hardware firewall/router.
I use PCTools. It's easy to learn.
Consider disabling or at least prompting for scripting/activex in the browser. Firefox with Noscript installed is excellent. Without Noscript, it's at least as vulnerable as any other. (Recent vulnerability found, yet to be patched.)
Run an antivirus, and let it update itself regularly. Run a scan with a good spyware scanner, like MBAM or Superantispyware or Asquared every week or two. Reduce in frequency if nothing is ever detected, and you gain confidence in the setup. Run immediately if "symptoms" occur.
There are other tricks and tips, too, including (especially) good backups, but that's a pretty good start that will keep you clean.