Hello - Thank you for the very helpful test page.
I'm using a Microsoft Life Cam Studio for Business with Win7 on Mozilla Firefox 74.0 (64 bit). It only turns on if I use sound recording software (for the mic) or your site (for both audio and video). This model doesn't come with any software, and I haven't been able to find any online, even on the Microsoft downloads and support pages. I've just downloaded Microsoft Edge, after reading about this in a support forum, to see whether it has any effect on the camera's function. Thank you for accepting questions.