Its more serious than just blocking the pop ups. The reason your getting the pop ups is because you have some sort of spyware/Adware camping out in your hard drive, using your resources. Its probably slowing your pc down. Im picking up my new pc this next week, and will definitely buy a spyware removal program for it so I can get optimal performance from my new 2.3 ghz machine.. (yea, had to gloss!
). I am also going to totally replace the hard drive I have in my current pc because its so full of spyware adware garbage I cannot get rid of it all. I cant even find it, but, it starts up when I start my pc. I get ads and Im not even surfing the web!
If you use the free version of Kazaa, that is your main problem. May I suggest paying for the Kazaa Plus, they claim that you will not get the pop ups. I will be paying for that service soon after I get my new pc, so Ill be able to tell you if its true or not.
Here is a free version of Spy Sweeper. You dont get all the stuff that the full version offers, but, it will scan and remove some spyware/adware on your hard drive. You will be amazed how much you have on your pc. I had 3000 traces!
I hope this helps.