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Sub Call_InstanceCheck()
'MsgBox InstanceCheck("outlook")
If InstanceCheck("Outlook") = False Then
UF_HINWEIS.Show
Else
If InstanceCheck("Outlook") = True Then
UF_NEUE_BESTELLUNG_EINTRAGEN.Show
End If
End If
End Sub

Function InstanceCheck(Server As String) As Boolean
Dim myInstance As Object
InstanceCheck = False
On Error Resume Next
Select Case UCase(Server)
Case "EXCEL"
Set myInstance = GetObject(, "excel.application")
Case "OUTLOOK"
Set myInstance = GetObject(, "outlook.application")
Case "WORD"
Set myInstance = GetObject(, "word.application")
End Select
If Not myInstance Is Nothing Then InstanceCheck = True
On Error GoTo 0
Set myInstance = Nothing
End Function