If that happens "all of a sudden", please check if you added another USB device lately. Remove the later USB devices and check if it works. Reflex normally needs no specific driver as it complies with the regular windows HID standard. You only need a specific driver if f.e. a Microsoft sidewinder joystick modifies the HID driver.

Furthermore:

Did you (or a windows update) change the energy settings for USB?
Did you try another USB port? The cases discussed here normally refer to front side and rear proprietary USB. Try the rear WITHOUT a hub.

If all doesn't work consider sending it to MRC for warranty exchange. Maybe there is something broken inside. Normally the Reflex USB interface is pretty easy to handle.