On systems running certain security applications (such as Novell), users are granted administrative privileges only to find that when they try to make certain changes to the system, "access is denied".
Here is a simple solution to this problem:

1: Open Command Prompt
2: Note your system time (let's say that it's 12:30 pm)
3: Run the following command:

at 12:31 /interactive cmd.exe

4: Exit Command Prompt and wait for the new window to pop up
5: Use Ctrl+Alt+Delete to open the Windows Task Manager
6: End your desktop process (explorer.exe)
7: Type "explorer.exe" in the new Command Prompt window
//Now you have complete rule over the computer.

Here's what's happening:
Certain tasks and applications are run from the "SYSTEM" account, including some security software. Often times you cannot modify these tasks/applications, even from an administrative account.
The "at" command tells the SYSTEM account to run tasks at a certain time. In this example, we use the "at" command to run command prompt, using the "/interactive" modifier to make this application accessible by the user.
Since cmd.exe was executed from the SYSTEM account, any commands you run in this prompt will also be executed from the SYSTEM account. So when we restart the desktop process, we're actually starting SYSTEM's desktop process.

Now you can mess around with the security applications installed on said computer, disable DeepFreeze, whatever you would like without any hassle.

Note: Administrative privileges are usually required in order for this to work, as no admin in his/her right mind would allow a user with limited privileges to schedule system tasks.

Regards,
Grey Fox