Remove NationZoom and CompareItApplication from IE/ Chrome/ Firefox Easily

Recently, some users complain that their PCs are attacked by NationZoom and CompareItApplication.

"Hello,
I think that my computer is infected with viruses. On Google Chrome and Internet Explorer, NationZoom has taken over and I am not aware of how to remove it. Also on Mozilla Firefox, Ads by CompareItApplication keep on popping up and I do not know how to get rid of that. I think that there might be other viruses on my computer. Please advise me on how I can fix this problem. Also, if I back up all of my information on my computer onto a hard drive, will resetting it to factory settings remove these types of virus? Thanks."