aspire vn7 791 - web cam - Unknown USB Device (Device Descriptor Request Failed) - win 8.1

Hello,

just bought the nitro vn7 791 and i can't get my webcam to work. found in device manager that i have an usb device with the following description: Unknown USB Device (Device Descriptor Request Failed)

Already tried:

1. unistalling the unknown usb device, unistalling the usb roots and draining the battery to zero. Then powering it up and asking windows to finding the drivers (when i drained the battery, i used a pin to to push the button that simulate the removal of the battery). did not work

2. installing the acer crystal eye (it says i don't have a web cam)

any thoughts?

ty in advance.

general:

Windows has stopped this device because it has reported problems. (Code 43)

A request for the USB device descriptor failed.

status:

01802400
DN_HAS_PROBLEM
DN_DISABLEABLE
DN_NT_ENUMERATOR
DN_NT_DRIVER

class guid:

{36fc9e60-c465-11cf-8056-444553540000}

device instance path:

USB\VID_0000&PID_0002\6&1665BF5E&0&5

hw ids: USB\DEVICE_DESCRIPTOR_FAILURE