In Windows NT 3.51 and 4.0, the WaitToKillServiceTimeout value name in the registry allows you to specify a length of time that the service control manager must wait for services to complete the shut-down request.
To specify the wait time, follow these steps:
1. Start the Registry Editor (Regedt32.exe) and locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:
\\SYSTEM\\CurrentControlSet\\Control
2. Highlight the value WaitToKillServiceTimeout
3. From the Edit menu, select String.
4. Enter the amount of time desired in milliseconds (the default is 20,000)
If a value is not present, select Add Value from the Edit menu and enter the following:
Value Name: WaitToKillServiceTimeout
Data Type: REG_SZ
String: <in milliseconds; default is 20,000>)
Note: Keep in mind that if you lose power, it is possible that your uninterruptible power supply (UPS) may not provide enough backup power to the computer to allow all of the services to shut down properly in addition to the shutting down the System. If you have a longer timeout value, the UPS may run out of power before the services run.
5.Click OK and then quit the Registry Editor to save the changes.