If you have seen the TV ads for stopsign.com, veloz.com, eacceleration.com or eanthology.com - Don't Go There! Those websites are known to secretly install several spyware applications, popup generators and trojan downloaders! They get away with it because before you can 'scan' your box, you click on a box to give approval for their 'process'. Of course, what they find and remove will be replaced with the software that THEY install so that the people that pay them will have their software on your box. They also will try to remove your other anti-spyware software, like PestPatrol and Ad-Aware. They may try to uninstall anti-virus software as well, as now several of the major AV vendors detect these websites as hostile.
So be very very cautious of any advertisements on TV that seem too good to be true. It's a shame that they are getting away with this.
If you want a good antivirus, look to Symantec/Norton or McAfee. If you want a good anti-spyware, look to Spy Sweeper or Ad-Aware. These flashy TV ad gimmicks are nothing but trouble!