I have tried several times to enable to fast user switching option in the user accounts, but everytime I try it disables itself, there are 2 accounts enabled on the computer 1 is the password protected, primary admin account, and the other is the guest account, I tried changing the option using the admin account, but failed, there is no error displayed or anything like that, just the option doesn't change, I would like the 'WINKEY+L' combination to work, so that I can change to the guest account when I have finished using the admin account, for other users to use the guest account, without having to log off each time.