Copied from the vba help file.....
AppActivate Statement Example
This example illustrates various uses of the AppActivate statement to activate an application window. The Shell statements assume the applications are in the paths specified. On the Macintosh, the default drive name is "HD" and portions of the pathname are separated by colons instead of backslashes.
Dim MyAppID, ReturnValue
AppActivate "Microsoft Word" ' Activate Microsoft
' Word.
' AppActivate can also use the return value of the Shell function.
MyAppID = Shell("C:\WORD\WINWORD.EXE", 1) ' Run Microsoft Word.
AppActivate MyAppID ' Activate Microsoft
' Word.
' You can also use the return value of the Shell function.
ReturnValue = Shell("c:\EXCEL\EXCEL.EXE",1) ' Run Microsoft Excel.
AppActivate ReturnValue ' Activate Microsoft
' Excel.
So if you know the path of the application, could you use the second example above and then check the value of MyAppID?