Do you have any other cameras connected to this PC? Did you install any specific updates of drivers or software?
First you need to find if the camera is recognized by the OS. Just disconnect the camera, open up the device manager and then connect the camera
If you have a sound card, you should hear a device connect sound, followed by a device disconnect sount, followed again by a device connect sound.
At that point you should be able to retrieve the device information from the device manager
If not, the camera or the USB port or the USB cable could be broken,
if the camera is listed, there is a driver installation issue somewhere (this is the best case scenarion)