Microsoft Security Center and Green AV

A few days ago, I got an alert that my computer was not protected and that I had viruses. An add came up for Green Av (cost $99.99) and Microsoft Security Center. I have McAfee and do not need this program. I have been unable to cancel these messages and these programs have taken over my computer. I went to the Microsoft website and sent an e-mail about this. I am still waiting to hear back from them. Interesting, their home page has a warning that the website may have spyware, adware, etc. and to get Green Av for protection. It interrupts everything. My daughter was unable to sign up for her unemployment compensation. If I do not get satisfaction, I will go to a lawyer and file a class action lawsuit. I am sure other people have gotten this ad and may have spent money that they did not have to