Check if a pointer points to a valid and running MS-Office instance. The function does this by first checking for NULL and nil pointer and then
trying to get the current selection of the application.
IsValidHwnd(hwnd)the pointer to a word instance as created by GetNewWrd() or GetCurrWrd().
Default is the last created pointer stored in DescToolsOptions("lastWord").
logical value, TRUE if hwnd is a valid pointer to a running application
GetCurrWrd(), GetCurrXL(), GetCurrPP()