Avoid Cyberdefender and My Identity Defender at all costs!
This is actually spyware/malware that will install a trojan virus on your computer that will a) display a "you've been infected - download this software" type alert, b) will sporatically restart your system on it's own, and c) will block you from going to any types of tech support sites, spyware removal sites, competitor sites, etc. The block comes in the form of a googlish search result page proudly diplaying their logo at the top. All links direct to their site.
I called tech support to have this "software" removed. The techs were the most unprofessional customer service reps I have dealt with period. Disrespectful, challenging and pushy.
They will not help you unless you a) sign over control of your computer to them (while they copy your files on the back end to obtain personal information), or b) pay their $99 premuim service. One of their techs actually slipped their tongue, saying "Sir, I will help you remove the virus... I mean our software".
Their "free help" includes walking you through add/remove programs in the control panel, and resetting internet explorer to factory defaults - very simplistic procedures. Beyond that, they say they need you to relinquish control of your PC to them or pay the $99 fee. I imagine they are able to trick many people who are less computer savvy.
I am appalled that this company is in business. This is a complete fraud to scam you of your money and obtain important personal information.