credo che ti stia confondendo...

shell("applicazione exe",modo di visualizzazione)

comunque per leggere txt:

Private Sub Form_Load()
Dim N As Integer
Dim strRead As String * 255
Dim i As Long
N = FreeFile
Text1.Text = ""
Open "tuo.txt" For Binary As #N Len = Len(strRead)
i = 1
Do While EOF(N) = False
Get #N, i, strRead
Text1.Text = Text1.Text & strRead
i = i + Len(strRead)
Loop
Close #N

per modificare tuo txt:

Dim myrecord As String * 1
a = Len(Text1.Text)
Open "tuo.txt" For Binary As #1
For i = 1 To a
Text1.SelStart = n
n = n + 1
Text1.SelLength = 1
myrecord = Text1.SelText
Put #1, n, myrecord ' Scrive il record nel file.
Next i
Close #1
MsgBox "SALVATO!!!"

ciao!!