If there is a problem with a driver or some other glitch preventing Windows 2000 from booting normally, Windows can automatically boot in Safe Mode. You may even want to manually boot Windows 2000 to Safe Mode.
For example, say you install a video driver that's defective or isn't compatible with Windows 2000, and you can't see the desktop properly to log on. Boot to Safe Mode (which loads a standard VGA driver), remove the other driver, and restart.

When the system begins to boot, press [F8] in order to display the boot menu, which offers the Safe Mode options.
You can find a list of services that Windows 2000 starts in Safe Mode in this key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Safeboot

• The Minimal key lists the services that Windows 2000 starts if you select the Safe Mode or Safe Mode With Command Prompt boot options.
• The Networking key lists the services that start when you select Safe Mode With Networking from the boot menu.

You also need to know that Safe Mode sets an environment variable named SAFEBOOT_OPTION, which specifies the current Safe Mode. You can use this environment in a batch file or script to perform tasks based on the mode in which you start Windows. If you boot using Safe Mode or Safe Mode With Command Prompt, the variable is set to Minimal. If you start Windows with Start Mode With Networking, the variable is set to Network.