We had a MS Explorer Mouse Model 1362 with a Red light flashing quickly. The mouse had been disconnected from its charging station for over two weeks. The fix was to connect it to its charging station while depressing the button in the bottom of the mouse (the button that detects when the usb transmitter is attached or not).
Ran into this again and the fix above didnt stop the red light from blinking. The solution this time was to replace the rechargeable battery inside the mouse with another NiMH Rechargeable battery. We used an off brand 2800mah instead of the stock 2100mah, and we have no issues charging, etc.