A good anti-virus program is a must for all PC users, but today there is also malware that even a good antivirus program may miss. Not everyone needs an anti-malware program, but when you think you may be infected, this is a good free program to use.
I used to use Ad Aware to detect malware, but that program has become a little bloated and it just doesn't seem to do the job. Another program has taken over as the top rated anti-malware program. And luckily, it's free. Malwarebyte's Anti-Malware, at this link: http://www.malwarebytes.org.