Verified answer

http://www.malwarebytes.org/mbam.php

Use the free version, update, do a scan

All are good but a lot of people do not update after they get them.

And it only takes a couple of minutes.

Make sure you update everday they are not automatic

Get an anti virus progam also male ware program and use scans on both.

Pick they are free. But only 1 anti virus and 2 male ware programs!!!!!!!.

Download these free scanners from these websites:

Malwarebytes' Anti-Malware: http://malwarebytes.org/

Malwarebytes is a site dedicated to fighting malware. Malwarebytes has developed a variety of tools that can identify and remove malicious software from your computer. When your computer becomes infected, Malwarebytes can provide the needed assistance to remove the infection and restore the machine back to optimum performance. Malwarebytes Anti-Malware is a surprisingly effective freeware antimalware tool. It's a relatively speedy malware remover, with the quick scan taking about 8 minutes even with other high-resource programs running.

SUPERAntiSpyware: http://superantispyware.com/

Detect and Remove Spyware, Adware and Remove Malware, Trojans, Dialers, Worms, KeyLoggers, HiJackers, Parasites, Rootkits, Rogue Security Products and many other types of threats. Light on System Resources and won't slow down your computer like many other anti-spyware products. Won't conflict with your existing anti-spyware or anti-virus solution! Repair broken Internet Connections, Desktops, Registry Editing and more with our unique Repair System!

AVG Anti-Virus: http://free.avg.com/

Protection against viruses, spyware, adware and trojans. Protects in real time against poisoned web pages while you're surfing. Real-time safety ratings for all search results in Google, Yahoo and MSN/Live search. Easy access to LinkScanner tools, built-in search capability.

Also the sight you get them from are legitimate.