Hi Jan-Kenneth Martizano,
1. Have you made any recent changes on the computer?
2. Do you receive any error message when you connect the web camera to the computer?
3. What is the make and model of the web camera?
4. When was the last time web camera worked fine on the computer?
Refer the below link and run the hardware and devices troubleshooter available, check if it works.
Tips for solving problems with USB devices
http://windows.microsoft.com/en-US/windows-vista/Tips-for-solving-problems-with-USB-devices
If the above step fails then check the status of the device on the computer using the device manager and post back the details.
a) Open Device Manager by clicking the Start button
b) Click Control Panel, click System and Security, and then, under System, click Device Manager. If you're prompted for an administrator password or confirmation, type the password or provide confirmation.