Go to http://www.google.com and type "Pop Up Stoppers" (without the quotes)
and hit search... You will find MANY small programs to do what you wish.
Some of them you have to buy but there are a bunch of free ones as well.
Here is a free one that is recommended. http://www.panicware.com/product_psfree_download.html
I have found a REALLY good program for that...it is called
Emerald PopStop. It is really excellent....you can read
more about it and download it from www.emeraldpopstop.com
it really is great!
You could get McAfee Internet Security. I think thats the
best or the free option is to download a little safe tool
called pop-up stopper from pacicware.com. Its also very
good!