Correct syntax for opening a file on another hard drive.

[rdfoto3]

Sorry to need to post this, but I'm very new, and simply want to open a database file on a different drive than my primary. In the script OnOpen I've added the line Open and then used the prompted file source at the bottom (which shows the correct file) but it doesn't open. When I run the script it just shows me the directory and I have to select the file. But I can't find a way to include the entire file path so it appears in the prompt window for the script. Surely it can't be this tricky. Help.