Sometimes when you are closing your Windows session, the processes and system applications that have access to two registry keys in the user profile will prevent the system from completely shutting down.
UPH Clean is a Microsoft utility that allows you to resolve a certain number of problems that arise when closing your session, as well as user profile access (especially with roaming profiles) and close access to these in the registry. This allows your computers session to close properly so that Windows can shit down.
This utility is aimed at processes that operate on Windows systems that are running the NT core (meaning NT4, 2000, XP and 2003). These errors correspond to 1000 (under Windows NT4 and 2000), 1500, 1517 and 1524 (Windows XP and 2003) in the event viewer.
Error 1000 on the “firefox.exe” process
Once the file has been downloaded you will need to run it to have access to the system service installation. If you don’t have the latest version of Windows Installer then you should get it here first. Note: Under Windows NT4 the computer doesn’t need to be rebooted for the service to immediately be operational. For the others this service will automatically start each time the session is opened.
It is possible to go into great detail with the UPH Clean settings and change some of the base settings of the registry (regedit.exe) and display the processes and applications that are causing problems at shutdown by change the DWORD value of HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\UPHClean\Parameters\REPORT_ONLY to 1.