Here's a function I wrote a few months ago to get a string representation
of the duration (in Days, Hours, Minutes). While it doesn't do seconds,
you could modify it to meet your needs.
Running this from Debug window produces the output: 0000:00:10
? GetDuration(#1/6/2004 1:03:36 PM #,#1/6/2004 1:13:36 PM #)
Public Function GetDuration(ByVal dStart As Date, dEnd As Date) As String
On Error Resume Next
Dim iDays As Integer
Dim iHours As Integer
Dim iMinutes As Integer
iHours = DateDiff("h", dStart, dEnd)
iDays = iHours \ 24
iHours = iHours - (iDays * 24)
iMinutes = DateDiff("n", dStart, dEnd)
iMinutes = iMinutes Mod 60 '- (iDays * 1440) - (iHours * 60)
GetDuration = Format(iDays, "0000") & ":" & Format(iHours, "00") & ":" & Format(iMinutes, "00")
End Function