In order to use a DLL, it has to be registered by having appropriate references entered in the Registry. It sometimes happens that a Registry reference gets corrupted and the functions of the DLL cannot be used anymore. The DLL can be re-registered by opening Start-Run and entering the following command:
regsvr32 somefile.dll
This command assumes that somefile.dll is in a directory or folder that is in the PATH. Otherwise, the full path for the DLL must be used. A DLL file can also be unregistered by using the switch "/u" as shown below.
regsvr32 /u somefile.dll
This can be used to toggle a service on and off.