I, too, have SP7 and none of these solutions work for me. Interestingly, the "Hello" log in feature seems to still recognize me from when it was first set up, but the front facing camera won't work for anything else. The rear cam works fine, but that doesn't help for virtual meetings.....
I would love Microsoft to step up to this and provide the right files and instruction to wipe out and reload the camera drivers...I feel like the camera must actually be ok, just a problem communicating with it from software packages. But, I'm just "the boss" who is mucho UN-happy about it but don't have staff to spend dozens of hours searching for and trying solutions...