one more thing you can do so stop spyware/adware from installing on your system is to get

1. spywareblaster : www.javacoolsoftware.com/spywareblaster.html
2. spywareguard : www.javacoolsoftware.com/spywareguard.html

you should also immunise in spy.bot and add the host entries to your host file.
spy.bot also comes with a inbuilt feature of blocking bad download in internet explorer you should also enable this.