My control panel does not appear

Hello,
my name is AHMED
my control panel hasn't appear anymore on the start list
for the exampel if i press the clock twice it appears me that< this operation has been cancelled due to restriction in effect on this computer . please contact your system administrator >
and i've already logged on administrator
please what i have to do
i still have this problem
by the way i've changed the name of administrator to another name like my name is that okey
I have windows xp service back 3