I've got a microsoft usb mouse that functions per normal until I plug in a Huawei 3g dongle. Then the mouse stops functioning and the 3g dongle connects successfully.
I have tried un-installing all usb drivers and it automatically reinstalls it at startup. Mouse functions again until I plug in the 3g USB device again. I have also tried plugging in USB memory stick and that doesnt cause conflict so it seems that the issue is only relevant to the 3g modem.
More aboutdevice conflict windows
The dongle is either defective or made poorly, and should be replaced.