Discover > Canceled Question

When I open my Outlook program I get the message in the center of the screen "PERSONAL FOLDERS - The path specified for the file F:\Outlook\Personal Folders File - notes.pst is not valid". When I click to delete the message or click the OK box a new message opens in the top corner of the desk top "Create/Open Personal Folders File" followed by a list of personal files. At the bottom of this box is a Personal File box and a Files Of Type box. There are three choices, "Open, Cancel or Help". Clicking on any of them or the X at the top of this box returns me to the first message at the center of the desk top. Repeated cancelling (six to ten times) opens my Outlook. I cannot find the source of these messages to stop them. Do you know the source or how to stop these messages?