In order to run this tech tip you need following things:
(a) VB5 or VB6
(b) Reference to Type Lib information object component (TLIBINF32.dll).

This function takes in the name of the com component (or dll) or the typelibrary which needs to be unregistered.

 Private Function UnregisterTypeLib(ByVal strTypeLibName As String) As Boolean    On Error GoTo ErrorHandler    Dim pTypeLibInfo As TLI.TypeLibInfo     ' Pointer to TypeLibrary Info object    If (Trim(strTypeLibName) = "") Then        MsgBox "Select a Type library file to unregister . ..", vbInformation +vbOKOnly, "File Selection Error"        UnregisterTypeLib = False        Exit Function    End If    ' Get the pointer to type library information for the specified file    Set pTypeLibInfo = TypeLibInfoFromFile(strTypeLibName)    ' Unregister the Type Library from the system registry    pTypeLibInfo.UnRegister    ' Release the reference to this typelib object    Set pTypeLibInfo = Nothing    UnregisterTypeLib = True    Exit FunctionErrorHandler:    ' Display the complete error message    MsgBox "Number      : " & Err.Number & vbCrLf & _           "Description : " & Err.Description & vbCrLf & _           "Source      : " & Err.Source & vbCrLf & _           "Help File   : " & Err.HelpFile & vbCrLf & _           "Last DLL Err: " & Err.LastDllError & vbCrLf, vbCritical + vbOKOnly,"Unregister Type Lib Error"    ' Release the reference to this typelib object    Set pTypeLibInfo = Nothing    UnregisterTypeLib = FalseEnd Function