Saying a virus scanner, such as Kaspersky, is better than the other yesterday will not apply today. They change like my coworker's hairstyle and she's still not attractive. Having the most and latest definitions is what matters. Every company have peeps searching for the recent viruses. If we got Joe Schmo working at Norton and he doesn't give a fuck about his job after his wife cheated on him, then the likelihood of him finding the latest malwares wouldn't be as good as happy Jane Doe who works at McAfee. His lack of productivity may mean you are not be getting the protection you should be getting and even giving "false positives".
What I can tell yall is to use more than 1 virus scanners when your system is infected. For obvious reasons, it's not a good idea to install more than 1 at the same time because interference will occur. If you can, uninstall one and install another. Also, use what OKhmer mentioned - Spybot Search and Destroy. It's great for spywares. I personally use this also, along with Ad-Aware.
I hope people don't get the wrong idea, but CCleaner isn't going to help yall when your computer is infected. All it does is clean all the junk in your computer. You can clean your computer yourself, if you know what you're doing - such as tossing your browser cookies away and even going into regedit and clean out the registries you no longer need, especially after uninstalls.
If any of you are more advanced, then you should know about hijackthis. It is an awesome application that detects malware and gives you a detailed breakdown on what's in your system.
Blah blah blah....for the rookies, if your shit is infected, just use more than 1 virus scanner, use Spybot Search & Destroy, and Ad-Aware, and you should at least clear out some boogers in your computer. I'd like to also mention that it would be a good idea to go into Safe Mode when using these apps.
FYI: some free virus scanners are better than the paid ones. Seriously.
Good luck. Hit me up if you have any questions.