Free Anti Spam Software

I have had problems with bit defender, AVG, and Norton.

I have McAfee Total Protection installed and it does not find anything. I also have run Microsoft Malicious Software too, with nothing found. I still keep getting these popups that are just ads. WHY?!?
Additionally:
My firewall is enabled.
McAfee Total Protection is supposed to cover spyware, adware, malware, etc. It’s as 12-in-1 product.
I ran adaware prior to purchasing McAfee and it found nothing.
Spykiller also found nothing.
My pop-up blocker is also enabled.

For about a week now, my internet has been getting interrupted by a popup from system doctor 2006 it’ll will keep sending me to the page cannot be displayed screeen and the first thing that it suggest is to install system doctor software to clean my PC. I already have eTrust software to check for viruses and spyware but somehow it didn’t notice this. So I was wondering, is system doctor 2006 legit? How can I solve this problem? I also have a protection bar toolbar that I can’t get rid from my browser. All of the links take me to one of these sites:

http://www.securetoolbars.com/remove_popups/
http://www.securetoolbars.com/remove_spyware/
http://www.securetoolbars.com/spam_protection/
http://www.securetoolbars.com/security_test/

These sites advertise:
AdProtect
WinAntiVirus
VirusBlast
WinAntiSpyware
AntiVirusGolden
Drive Cleaner
Pest Trap
System Doctor

I have never heard of any of these products. Any help that is given is appreciated.

I just got a new lap top and I refuse to use McAfee because last time I got a virus inside of it. I heard AVG is really good is this true?
AVG also has a version that you can pay for as well as anti-spyware. How good is that?