Did you install all drivers after re-installing the operating system? Click on the link below for steps on how to use the Dell Drivers & Downloads Website to download drivers:
Drivers & Downloads for Studio 1749: http://dell.to/17kCUVY
Since the hard drive crashed and you have re-installed the operating system, you may have to re-install the Webcam drivers from My Dell Downloads Software link.
My Dell Downloads Frequently Asked Questions: http://dell.to/19qs2I5
If you still face issues, please click on the link below to troubleshoot issues with the webcam:
When these steps do not resolve the issue, a diagnostic test is available for the webcam. Run the Dell PC Diagnostics for Webcam Issues.
Link for Dell PC Diagnostics: http://dell.to/1bjGJxZ
Let us know if further help is needed.
Thanks & regards,
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