The "Control Help Window" only has "Show" and "Top Left Corner" inputs. You are probably talking about the "Control Online Help" function. You can use this function to display a compiled help file or HTML files in a web browser.
I've included a VI, compiled .hlp file, and an .html file. Both of these can be opened with the VI. The VI was created with LabVIEW 6.1
Zvezdana S.