Hi yaz00, welcome to the HP Forums. If the webcam is still not working after a system restore, it is quite possibly a hardware failure. If a Windows update causes the issue, you could simply roll back the driver to the original: Restore a driver to its previous version.
Here is all of the available troubleshooting beyond that theory: Webcam Troubleshooting (Windows 7)
Also make sure there is nothing covering the webcam lense.
I hope this helps.