I have a HP Pavilion dv9715nr entertainment laptop which has done the same thing. Webcam does not exist, but there is an unknown USB device, error code 43. I know it is not a Toshiba but I have seen the same problem all over the web in forums about many different makes.
To cut to the chase, I have finally found that HP don't support Windows 7 on my model.
They have a list of models that they will do updates for to ensure Windows 7 compatibility, mine is not on it.
It actually specifically refers to this in the HP support section that webcams may not even be recognized, that is my (and yours too I think) problem. Device manager can't see any imaging device and lists it as an unknown usb root controller device. Driver
is 6.1.7601.17586 , 21-June-2006- port #2 hub #3. (which means nothing to me)
End result is 'no video device detected' even after scan for hardware changes, disabled/uninstalled device and restarted and so on, nothing has worked.
I am hoping perhaps some kind of 3rd party may have whatever it will take (driver, BIOS update??) to get it going with Windows 7, because HP basically say use recovery and go back to vista. I'd prefer to stay with Windows 7 myself.
So does anyone know how we can get these suckers going if the manufacturer says tough cheese?