When I tried to install Norton System Works on my computer, I followed all of the prompts and instructions. The old antivirus program was supposedly uninstalled in the process. I then installed Norton System Works on my computer. When I restarted my computer it gives me a warning saying that before I can install Norton System Works (which I thought I had done already) I need to uninstall the previous antivirus software (which I thought I had also done already). The computer then starts this loop of shutting down and restarting over and over again with the same warning message. I have tried to remove the all antivirus programs but the computer shuts down and restarts before I get a chance to finish. What did I do wrong and how can I fix this problem?