可以試試這個, 但不保證.

Problem:
My USB device will occasionally lose connection to the computer, and I have to disconnect and then reconnect it before it will work. Why does this happen, and how can I get Windows to redetect the device, without having to physically disconnect the device?

Solution:
This behavior occurs when the device loses power, but the computer does not. For example, often when a computer goes into standby or power-save mode it will often shut down power to the USB ports. Also, this can happen when a computer returns from having been hibernated. In either case, the device is not redetected by the computer and thus you will not be able to communicate with it. Follow the instructions below to redetect the device within Windows when this happens:
Install the DevCon utility from Microsoft. The DevCon utility is a command-line utility that acts as an alternative to Device Manager. Using DevCon, you can enable, disable, restart, update, remove, and query individual devices or groups of devices. You can download DevCon from http://support.microsoft.com/kb/311272.

If you are running Windows 7, it is recommended that you download DevCon as part of the Windows Driver Kit (WDK) 8.0. This can be downloaded from
http://msdn.microsoft.com/en-us/library/windows/hardware/ff544707(v=vs.85).aspx.

Open the Windows Device Manager by going to Start » Run, type in devmgmt.msc, and then click the OK button.