This question is far from having been answered.
Please change its status back to 'unanswered' or 'not yet answered' or 'pending', and leave it as such until a definite answer works for all of us.
A few more more thoughts:
1. When (trying and) adding an 'imaging device' as legacy in device manager, why can we not see the Quanta webcam under Dell in the list?
2. Or a list for all Quanta webcams?
3. And why, after downloading and installing the driver from the dell drivers web page, do we still not see it appear anywhere (e.g. in the list of 'legacy hardware', or other via device manager),
4. and why still does it not work when one chooses, through manual addition and 'Have disk...', the directory where said driver has been unzipped?
Thank you.