The Best Catty is
Spywareblaster 
which stops 99% at source Doesn't have a chance to latch onto your machine to start their "tricks"
and its Free!
www.javacoolsoftware.com Screenshot and review here (download from here also)
www.spychecker.com/program/spywareblaster.html once this is installed you can throw all your Popupstoppers in the Recycle bin and you can wander about with only a tiny chance of picking up a Popup Ad Generator
Should you want to give it a go ? here are the setup instructions:
The first thing you do is take a
"System Snapshot" which acts as a foundation also a reference point to rewind to, should the program run into trouble(never happened yet it is very strong)
Next press the
"Check for updates" button to populate the list then press the small button under the list
"Select All " which will tick all the boxes on the list in red
Next click the large button called
"Protect against Checked items!" This will turn the list to black and should generate a tiny
"success" box
Thats all there is to it Catty.
Every month, return and hit the "Update" button,there always seems to be more stuff added
At the time of Posting there are 1195 items on the list! 
A minutes work Tops a month !
Googles toolbar is good as an additional barrier against this plague
work with the tool bar the warning noise is like a machine gun running full pelt ,but add
Spywareblaster into the equation you'll get perhaps 1 or 2 clicks per hour.
)
