This is often caused by your computer turning of the USB, to change the power settings of the USB follow these steps:
- Go to Control Panel > System > Hardware tab > and click on the "Device Manager" button
- In the Device Manager, find the item or items labeled "Universal Serial Bus controllers." Open it, and double-click the first item called "USB Root Hub"
- In the USB Root Hub Properties dialog, click on the "Power Management" tab
- "Allow the computer to turn off this device to save power" is checked by default. Un-check this box, and click "OK"
If this does not help, create a ticket to the support.