@ arnelgp..
thanks for the reply...I tried that code and executed this below query ,,
[Forms]![Navigation Form]![RecordSubform].[Form]![Label17]>=8
but again i get the Else Msgbox .."No user Logged in morethan 8 hrs".
but my subform consists of 2 values morethan 8 hrs..
07/27/15 04:58:26 PM...