To disable Deep Freeze:
Hold down the shift key and double-click on the Deep Freeze icon. Alternatively, you can press Crtl-Alt-Shift-F6. You should now see a password dialog.
Enter your password and click OK. If you have not yet entered a password you should be able to click OK without entering anything. You should now see a dialog with boot options.
Select "Boot thawed" and click OK. This will disable Deep Freeze on the next reboot.
Reboot your machine. After the machine reboots you are ready to uninstall Deep Freeze.
Locate the installation file you used to install Deep Freeze to this machine. 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"
The software should uninstall and reboot the machine. When the machine reboots, Deep Freeze should be uninstalled