Not too sure, but try this step:
7. Once again, goto Device Manager. Under Universal Serial Bus Controllers, you should see 4 entries named “USB Root Hub”. The 3rd one should be for the camera. Double click on it and select the Power Tab and make sure you see something like “Sony Visual Communication Camera VCC-U01” under the Attached devices label. If thats not the case then select another USB root hub and try the same. Now, click on the Power Management tab and uncheck the entry which says “Allow the computer to turn off this device to save power.” Click OK and exit device manager.