I also use Sandboxie which will isolate your browser or most other programs in a protected virtual environment. I almost never use it for surfing but it's great for checking out installs of applications that you're not sure you really want.

I do think the whole PC danger thing is overblown and/or the result of people not following the most basic procedures. Use a firewall and an anti-virus and 95% of potential problems go away. Install them, set the automatic updates and you're done. I'm glad users of other systems  feel safe, but honestly with a modicum of common sense, Windows is a safe environment despite notions to the contrary. That's my opinion anyway after many years of fairly imprudent computing :-)

" i might have to give avast a try"

I think any of the major free AV programs are about the same. I've used AntiVir, AVG and BitDefender at various times. Avast happened to be a smaller download, it works well and has frequent small updates. While I love Comodo's firewall, their AV was a work in progress. I'd stick with one of the established companies in that area.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken