There is another user logged on to this computer

[Tebza]

:knock: someone please help.
When i shut down my computer it always gives me the message that
'There is another/other users logged on to this computer' what is going on coz as far as i am concerned i am the only one on the comp.
Please advise. Very worried!!!!!

 

[RealBlackStuff]

Install Antivirus and a Firewall program. Then come back with a whole load more information please.