RESTRICT CHANGING CLOCK IN WINDOWS TIME DATE

to remove access to the clock you go to START>SETTINGS>CONTROL PANEL>ADMINISTRATIVE TOOLS> LOCAL POLICIES>USER RIGHTS ASSIGNMENTS> DOUBLE CLICK ON CHANGE THE SYSTEM TIME. (OR TYPE IN FROM THE RUN LINE SECPOL.MSC and start at local policies as above.

by default it has the administrator and power user groups. Remove both groups and then log off and back on and now ANY USER will not beable to change the time on the PC, it will give you a message that you do not have security permissions to change the time.