Do you want to uninstall Microsoft One care antivirus?
You should remove it by their proper Microsoft one care removal tool.
If you try to uninstall it by add/remove program, it doesn’t remove it completely, because some of security registries entries might be still remains, which can be create problems.
If you don’t use removal tool you might be facing the problem like: Computer freezing, Unable to connect internet, computer speed slow and also might be getting installation error.
Download the removal tool and uninstall it completely.
Download Microsoft OneCare Removal Tool