Click Start and choose Settings, Control Panel. When Control panel opens, double-click the System icon. When the System dialog box opens, click the Startup/Shutdown tab. Under System Startup, you'll see a spin box labeled Show list for XX seconds. Use the spin box to set the number of seconds you want the system to wait before automatically starting the default operating system.

In Windows 2000, its just as easy: Once you get to the System Properties dialog box, click the Advanced tab, and then press the Startup and Recovery button. You can use the spin box to change the number of seconds, or you can type the number manually.

After you set the time, click OK to close the dialog box and save your change. The next time you restart, the new time will take effect.