You don't need any additional security software for modern Windows machines. Windows Security, which comes built in with Windows, includes a perfectly adequate firewall and anti-virus program.
To switch from a third-party program to using Window Security, all you should need to do is to uninstall the unwanted software. That can often be done just by using the normal Windows 'uninstall' path but (because security programs are designed to be hard to remove) it's occasionally necessary to download and run a special uninstall tool from the website of that third-party program.