We have lost our control panel on our main and only logon

When we right click on the desk top and select properties we receive this message

"The operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator"

Like I said above we are the only logon, so I would guess we would be the system administrator

Can someone please advise what we can do to undo this so that it will enable us access to our own control panel

Please help it's driving me crazy :smileytongue:

Thanks