how can i connect my cam to my computer?it was working properly but now shows a message that the cam is not connect to the computer my camera is from the manufacture place to my laptop

Check whether the Drivers are Missing Or camera Is Disabled and Also check it is plugged correctly if it is a  external one. 

Search in the internet for Drivers for your model if drivers Are Missing

To check Drivers and whether it is disabled go to my computer and click Properties and go to Device Manager.