Hi

Not 100% sure what all you are doing here but you could do the
following

Add this line of code to the workbook open event

Private Sub Workbook_Open()
UserForm1.Show vbModal
End Sub


Add this code to the userform


Private Sub ComboBox1_Change()
Dim Name As String
Name = ComboBox1.Value
If Name = "" Or Name = "0" Then
MsgBox ("You should select the right name. This macro stosp here.")
ActiveWorkbook.Close
Sheets("Curstellingen").Select
ActiveSheet.Delete
Sheets("Datablad").Select
End
Exit Sub
End If


With Cells.Find(What:=Name, After:=ActiveCell, LookAt:=xlPart)
ActiveCell.CurrentRegion.Select
Selection.Offset(0, 1).Resize(4, 1).Select
Selection.Copy
End With

End Sub

Private Sub UserForm_Initialize()
ActiveSheet.Columns("A:A").Select
ComboBox1.Clear
Dim column As String
Dim i
i = 1
Do Until Cells(i, 1) = ""
ComboBox1.AddItem Cells(i, 1)
i = i + 1
Loop
End Sub

This should load your userform when you open the book and then you can
run your code from there...

S