I am a newbie.

Question

I am a newbie. I have Vista premium. Norton security system was installed with the computer. I have just gone on line for the first time so I need a seurity system. I purchased Windows Live Care One but in order to finish installation any security system needs to be uninstalled. But when there is an attempt to uninstall the Nortons an error comes up that says that the module can't be found. Whatdo I do?