I also use spy bot, ad aware but i have also found a malware removal tool at http://www.ewido.net/en/ . Ewido antmalware got rid of stuff I had no idea was there and I think for the most part I take good care to protect my system. It has a free scan and removal too so its nice to run and make sure nothing is slowing your system down that shouldn't be there.

I thought i saw someone say that Firefox was only availible for mac, but I run it on my pc and I like it much better than IE.