Hi Kim,
Yes I've tried that and it doesn't make any difference. I can unplug it, try different USB ports, uninstall and reinstall it, and nothing fixes it. The only way that I can get it to work is to reboot the laptop which works every time. I agree that it may not be the device itself, but I don't have this problem with anything else. I may try a different laptop, but this gives me a problem as it's the only one that I have a docking station for and it'll be a real pain having to plug everything in each time. As well as the camera I have a midi input and an audio interface.
Logitech have agreed to take it back, but I'm reluctant to return it as I think that a replacement may have the same problem and I can't see any alternative for the same sort of money that looks as good.