Option Explicit
Private Sub Command1_Click()
Dim appid As Long               'Problem !
appid = Shell(Chr(34) & Dir1.path & "\" & File1.FileName & Chr(34), _
  vbNormalFocus)
AppActivate appid
End Sub
 
Private Sub Dir1_Change()
File1.FileName = Dir1.path
Label1.Caption = Dir1.path & File1.FileName
End Sub
 
Private Sub Dir1_Click()
Label1.Caption = Dir1.path & File1.FileName
End Sub
 
Private Sub Drive1_Change()
On Error GoTo E1
Dir1.path = Drive1.Drive
File1.FileName = Dir1.path
E1:
MsgBox "Fehler! Laufwerk nicht verfügbar!": Exit Sub
End Sub
 
Private Sub File1_Click()
Label1.Caption = Dir1.path & "\" & File1.FileName
End Sub
 
Private Sub File1_DblClick()                                 'PROBLEM!
Dim appid As Long
appid = Shell(Chr(34) & Dir1.path & "\" & File1.FileName & Chr(34), _
  vbNormalFocus)
AppActivate appid
End Sub
 
Private Sub Form_Load()
Dir1.path = "K:\"
End Sub

LG,Robert