Find which Windows program is accessing a external device like a web cam

1. You need the devices "Physical Object" name, you get this by doing to "Device Manager" and double clicking on the device and switching to the details tab.
   
   From there you can use the drop down box and select "Physical Object", right click on the value and select copy.
   
   
2. You will need Process Explorer for this part.  you can get it from the following location:
   
   Process Explorer - Windows Sysinternals | Microsoft Docs
   
   
3. Run Process Explorer as administrator and then go to Find and select "Find Handle or DLL"
   
   
4. Paste in the "Physical Object" name from step 1 and press search.
   
   You will need to give it a few minutes as it can be slow.

Once its listed the process you can see if its being accessed by programs you where expecting of it something else is going on.