Q: macbook update to snow os x but webcam not working

Here are my best suggestions for your camera problem.

Try each in order until you find the one that solves your trouble:

 • Restart your Mac and check again to see if the camera works now.

 • If not, use your Mac's Disk Utility to repair permissions. 

    Then check again to see if the camera works now.

 • If not, Apple's http://support.apple.com/kb/HT2090 suggestions may help you.

    The proper "reset" suggested there for your Mac sometimes restores normal function.

 • If not, download and apply the latest Combo Update, for your Mac OS.

    The current one for OS X 10.6.8 is at http://support.apple.com/kb/DL1399

    Repair permissions again immediately following the system restart

    that completes the Combo update. 

 • If your trouble continues, the problem may be caused by a hardware problem. 

    There are no user serviceable parts of the camera.  For hardware help,

    contact Apple or an Apple-Authorized Service Provider for service.

    Unless you have a current backup, make one now.  

    Then use the final "Troubleshooting" suggestion:

     "... contact Apple or an Apple-Authorized Service Provider for service."