Why does File & Printer Sharing for microsoft network uncheck itself

I have several laptops that seem to be experencing this issue. I will not be able to manage the machine services remotely after investagating the issue I found in the properties of the local area connection that the “File and Printer sharing for Microsoft” was unchecking itself. if I put the check in and apply I am able to manage the machine. My question is what could be causing the machine to uncheck these settings the user who has access to the machine can not modify these setting. Have scanned for virus & spyware, machine is clean. any ideas would be good.