The camera itself may also have issues but is not as likely as a bad cable or incorrect drivers.
Also try different usb ports on the PC to make sure that one has not failed causing the device to not be recognized. Maybe try a different device with the cable just to make sure its not the cable causing problems. You may also want to check the cable for any damage. Not sure if the camera came with any software and drivers on a disc that you could try and reinstall? I have had this problem with many devices and it usually is a driver issue. Once the PC reboots it should notice that the camera is plugged in, and then windows will install a new driver for the device. Make sure to have the camera connected to the PC when you reboot. You may need to reinstall the correct driver or uninstall the camera in device manager and reboot the PC. If you locate it in device manager then you may want to see what driver it is using and if its functioning properly.
Open device manager and see if the device is listed anywhere. If you are using a windows computer and the PC does not recognize the camera then I would go to the windows control panel and under hardware and sound locate the device manager.
