This problem can occur due to various reasons, some of them include, corrupted webcam application or software, corrupted webcam drivers, etc.
Test your webcam with a new webcam application (you may try with Yahoo Messenger, Skype, Windows Live Messenger, Quick play, Youcam, etc)
Check if the webcam works with the new application.
If the webcam works well with the newly installed application, then the problem could be with the built - in webcam application or with the one that you have been using earlier.
Uninstall your previous application (the one with which the webcam did not work) and reinstall it.
Check now, if your webcam works.
If the webcam does not work, use the one with which your webcam works.
If the webcam does not work with any of the applications or software, then the problem could be with the corrupted webcam drivers.
Press and hold Windows Key and break key simultaneously.
In the System Properties window, select Hardware tab and click on Device Manager.
Click on "+" sign next to Imaging Device and check for any yellow exclamation mark beside the webcam device, if there is a mark, then it indicates that the device is in bad condition.
The device may function even at this situation but also can fail sometimes.
If you don't find any exclamation sign next to the device, then follow the below steps to isolate the problem.
Reinstall the webcam drivers from Recovery CDs or from the Recovery Partition in the notebook.
Just check now if your webcam works.
Also test the issue by reinstalling the new drivers from the webcam support link and if you are using the webcam application that came with your notebook then visit your notebook support website and in the drivers page you will be able to find the recently released webcam drivers.
After reinstalling or installing the new drivers check for the problem.
Ensure that the Startup type of Windows Image Acquisition (WIA) service is set to Automatic, if not set it to Automatic. WIA is a service that is required for running the webcam applications in the system and needs to enabled.
You can do this from Services, click on Windows key and R simultaneously to open the Run window.
Type services.msc in Run window and click on OK.
Now in the Services window, scroll down to Windows Image Acquisition (WIA) service and check its Startup type. If it is not set to Automatic, then double click on the service and set it as Automatic (beside Startup type) and click on "Start" to start the service and click on Apply. Click OK.
Check if your webcam works now.
If the problem still persists, then the issue could be due to an internal webcam hardware problem.
Before concluding if the problem is related to hardware, please check in your notebook support website for any diagnostic tools that you can run to fix these issues and sometimes you might have to be online to perform these diagnostic tests.
If you are running Vista in your notebook, ensure that it is Vista Service Pack 1.
If not, upgrade to Vista Service Pack 1 since it comes with a new webcam driver which is like a hotfix to the one in Vista.
To upgrade from Vista to Vista Service Pack 1:
Please visit the below weblink from where you can update or download it:
The webcam may not work even when your system resumes from Hibernation or Standby mode. This happens because most of the video applications could not adjust to the change in the Power State of the system.
To resolve this problem, restart your webcam.
If restarting will not resolve the problem then restart your computer which will resolve the issue.
The general procedures have been mentioned, there might be few more steps that have to be followed to isolate the problem. Please contact your support for this.
Thank your visiting my article Webcam of my laptop will not function Or the webcam does not work
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