If someone is controlling your mac laptop/desktop you need to disable screen sharing, it is an easy fix:
Here is what you have to do:
Logon as an admin.
1- Go to "system preferences", go to "sharing", The options you wish to uncheck are as follows:
Remote Management
Remote Login
Screen Sharing
2- Enable your Firewall:
Go to "system Preferences", go to "Security", Click "Start" to enable firewall.
3- Click "Advanced" Click on "Block all incoming connections" or enable "stealth mode", and "auto allow signed software to receive connections"
(*) You may need to unlock these items click on the "padlock icon" in the lower left corner and enter the admin name and password.
Wessam