See below definitions
Antivirus or anti-virus software is used to prevent, detect, and remove computer viruses, worms, and trojan horses. It may also prevent and remove adware, spyware, and other forms of malware. This page talks about the software used for the prevention and removal of such threats, rather than computer security implemented by software methods.
Deep Freeze, by Faronics, is an application available for the Microsoft Windows, Mac OS X, and SUSE Linux operating systems which allows system administrators to protect the core operating system and configuration files on a workstation or server by restoring a computer back to its original configuration each time the computer restarts.
Base on my understanding, both are protecting PC but in different field. However, mas best kong ang duha gamiton having a good PC Specs.
If you alone are using the PC then better have antivirus pero kong multi user na ang pc which is pataka lang ang uban ug delete, install uninstall better used both.