Video starts and immediately stops when using laptop's integrated webcam.

Hi,

I am using a Dell Precision M4800 laptop.  When troubleshooting my built-in webcam, I tried everything recommended in Zoom's Knowledge Base.  In Windows 10's settings, I made sure that the camera is turned on in Camera Privacy, and that desktop apps are allowed to access it.  When I join a meeting or start my own, and turn on my video, it stops a second or two after I turned it on.  A web search for "test webcam" takes me to a website where I can test the integrated webcam.  I get the error that it is being used or blocked by another application.  I checked for the latest Windows 10 updates, which supposedly updates the camera drivers.  Additionally, in Device Manager, I disabled, reenabled the camera, uninstalled, and used Scan for Hardware Changes, to detect and reinstall the drivers.  I also ran Microsoft's "Get Help" troubleshooting app on camera issues, and attempted to use the default video camera driver.  I also went to Dell for my Precision M4800, and downloaded Dell's Support Assist, to check for any manufacturer camera drivers.

After all the above steps, I still get the webcam blocked or used by another application error.  What else should I try?  How do I know when I should take my laptop in for professional help?  Is it possible, and how much does it cost to replace the built-in webcam?  Where would you take your laptop for professional help with the integrated webcam?  If using your 2020 iPhone SE as a webcam, how would you set that up?  If not, what kind of external webcam would you buy?  I am meeting with customers who need to see me.

Any help would be greatly appreciated.

Thank you,

Mike