If you want to uninstall a security program, the first place to check is your start menu [Start > All Programs] to see if there is an uninstall icon in the programs menu folder. If you find one there, it's likely to do the job. If you don't find one, go to "Add or Remove Programs" in Windows. Failing those, go to the program publisher's website and see if you can find instructions there. [more]
Be sure what you find is specifically for the product you want to uninstall. Instructions for "Emperor 2006" may be totally wrong for "Emperor 2003". You also need to be meticulous in following the instructions. Sometimes you must download a special tool to uninstall a program (see below).
You'll need to close the program before you actually uninstall it. Often, you'll be reminded if you forget, but the best policy is to shut it down first. There are a couple of main ways to exit security programs. One is from the icon in the System Tray (right-hand end of Windows' Taskbar) or from the console for the program. Typical ways to access these methods is by double-clicking or right-clicking the icon in the System Tray.
You may need to resort to using the "Task Manager" to shut down a stubborn program. [Start > Help and Support > search for "task manager" > select "Using Windows Task Manager"]
If you aren't successful uninstalling a program, try re-installing the program to get it back to its original state. The uninstall process may work then.
Many security programs bury themselves deeply into Windows. It makes them more effective, but they hang on with more tenacity when you try to remove them. Some simply refuse to uninstall, and others leave troublesome bits that can interfere with other security programs.
AppRemover is a general purpose tool for removing a wide range of stubborn security programs.
Some security programs, for example, ProcessGuard, are designed to protect security programs from being uninstalled. You may need to shutdown or disable programs like that before you can uninstall another security program.