Disable Deep Freeze before uninstalling it.
To disable Deep Freeze:
Hold down the shift key and double-click the Deep Freeze icon. Alternatively, you can press CTRL+ALT+SHIFT+F6.
Enter your password and click OK.
If you have not yet entered a password you should be able to click OK without entering a password.
The Boot Options dialog is displayed. Select "Boot Thawed" and click OK. This will disable Deep Freeze on the next reboot.
Reboot your computer. After the computer reboots, you are ready to uninstall Deep Freeze.
To uninstall:
Locate the installation file you used to install Deep Freeze on your computer. By default, the name of this file is called "DF5Std.exe" for versions 5.X and "DF6Std.exe" for versions 6.X.
Run the installation file (DF5Std.exe or DF6Std.exe).
Select the option to "Uninstall"
Deep Freeze is uninstalled and your computer is rebooted.
Source:
Faronics Suport Portal - How do I uninstall Deep Freeze?