DeepFreeze is a fascist program by Hyper Technologies typically used in schools. It consists of a VxD (driver), and a status program. A 60-day trial is available at

Mainly, it's billed as an anti-hacker/security program. It doesn't place any real restrictions on a system except this: ANYTHING done to a machine disappears with a reboot.

The driver appears to put itself in the Interrupt 13h (hard drive) interrupt chain, and points reads and writes destined for the hard drive to a virtual space. The upshot of this, as mentioned, is that all writes are temporary, until reboot.

Of course, this can be bypassed by booting from a floppy, preventing the VxD from loading. If your sysadmin is worth his/her salt, this will be disabled at the BIOS. It also insinuates itself into the BIOS read and write routines, keeping BIOS password crackers from operating.

Once installed and protected properly, you can format C:, install anything, uninstall DeepFreeze (it's in the Add/Remove Programs), and do pretty much anything you can inside Windows, and no harm will come to the machine.

The Freeze state is indicated by a small icon in the system tray. When DeepFreeze is disabled, the icon has a flashing X over it. When it is enabled, the icon .. doesn't have the X. To disable DeepFreeze, you bring up the password dialog (with a hotkey: Ctrl-Alt-Shift-F6, or by shift-double clicking on the icon), enter a password or OTP, and choose between the 3 relatively straightforward options.

  • Boot frozen
  • Boot thawed for next _ restarts
  • Boot thawed

DeepFreeze comes in a Professional and Standard edition.

The Standard edition freezes all local hard drives with a password set at install time.

The Professional edition is much more interesting. It has an "Administrator" program, which allows you to make (both silent and verbose) install packages, with more options than the Standard edition.

  • One time password capability is offered. Your admin, instead of using a fixed password, simply scribbles down the token to be had by opening the password box and takes it to the Admin program, and comes back with the aforementioned one-time password.
  • It can be configured with a thawspace, which shows up as another drive letter (Usually T:, but again, it is configurable). Data saved here is exempt from DeepFreeze.
  • It can also be set up to reboot machines at specified times, as rebooting will return them to the frozen (and hopefully pristine) state.

There is a way to disable it from a floppy, but if your admin is competent, you will not be able to go this route:

  • get a DOS boot floppy and boot from it. Duh.
  • Move the file c:\windows\system\iosubsys\persifrz.vxd to a safe location. If you want to totally nuke DeepFreeze, erase that file.
  • Reboot. DeepFreeze will flash it's X icon until that file is placed back. If you want to get rid of that, too, remember that DeepFreeze is available in the Add/Remove programs.