What is required in terms of reference material to learn how to have an app determine if an instance of itself was already running when the user tries to open one of it's main forms, then second instance make the original instance open the form, and then quit.

I.E. An app I am writing runs 5 or 6 top level forms. Each of these forms have a menu option to 'oapp.do(formname)'. The original instance of the app is run by myexe(formname) from Windows. This gets the app to create the main object (oapp) and then the do method opens the form and initiates a read events. At this time the user can run the clients and inventory (for example) separately from Windows. If clients form is already open, running inventory from Windows will create a second vfp app to run the inventory form. What I want is for the second instance of VFP to detect the first then call this one's do method with the form name, and quit.

Is WSH the way to go, Do I have to learn about COM? What is the best way to do this? So far I have not strayed far from the generic VFP path and gone into API's, COM etc...