Robert,
You most likely uninstalled correctly but the Anaconda directory is still on your system. Open up a command window and run "dir" to list your user directory. You will have either Anaconda, Anaconda2, or Anaconda3. To remove it I believe this works on most versions of Windows, be sure to put the correct Anaconda name you found from "dir".
rmdir /s Anaconda
After this you should be able to reinstall. As for the anti-virus you will need to tell the software to allow the Anaconda application or ipython you want to use. As far as how to do this I am not certain as I do not know what anti-virus you are using.