command button time limit

Ok, so:

Private Sub CommandButton12_Click()
Call PlaySound, time_limit
time_limit = Now() + TimeValue("00:00:05")
do until now() > time_limit
t = Now() + TimeValue("00:00:05")
myTime = Format(t, "hh:mm:ss ampm")
loop
End Sub

would continually run that code for 5 seconds.