Option Explicit
 
Dim d As Date
 
Private Sub Command1_Click()
    Dim sZeit As String
    Dim h As Long
    Dim m As Long
    Dim s As Long
    Dim gesS As Long
    Dim pos1 As Long
    Dim pos2 As Long
 
    sZeit = txtZeit
    pos1 = InStr(1, sZeit, ":")
    pos2 = InStr(pos1 + 1, sZeit, ":")
    h = CLng(Left(sZeit, pos1 - 1))
    m = CLng(Mid(sZeit, pos1 + 1, pos2 - pos1 - 1))
    s = CLng(Right(sZeit, Len(sZeit) - pos2))
 
    gesS = s + 60 * m + h * 3600
    d = DateAdd("s", gesS, Now)
 
    txtErgebnis = CStr(d)
 
    Timer1.Interval = 5000
    Timer1.Enabled = True
End Sub
 
Private Sub Form_Load()
    Timer1.Enabled = False
End Sub
 
Private Sub Timer1_Timer()
    If Now > d Then MsgBox "jetze isses soweit", vbInformation
End Sub

Gru? Michi aus Hannover

1 + 1 = 3 f?r hinreichend gro?e 1