1. Restart your PC.
2. Press DEL or F2 shortcut to CMOS setup in short goto CMOS setup.
3. Change the date 10 years backward or forward. Then save it and restart PC.
4. Before the windows logo shows up Press F8. There you can select safe mode, safe mode with network, etc.
5. Choose Debug mode or Debugging Mode.
6. In Debug mode select the OS you use for example windows xp pro.
7. (This is need a little quicker of hands) When the windows XP starts wait the welcome screen appears and make your fingers get ready to press CTRL+ALT+DEL shortcut key for taskmanager.
8. After the windows XP welcome screen the Windows desktop will appear. Quickly hit CTRL+ALT+DEL.
9. Press D 'D is the shortcut key to locate the process DFServ' or you can locate it using your mouse. After locating it press Del 'to kill the process DFServ.'
10. If you succeed restart your PC and boot it in normal mode. There you can see the deepfreeze icon will be mark X means it is disabled. Now you can uninstall it using deepfreeze installer.
After making those steps don't forget to change back your time in CMOS.