I have similar problems from time to time with my Logitech wireless mice (using Windows 7) and one or the other of two solutions has always worked for me. If the mouse pointer has simply slowed down or become erratic, it's usually dust and simply blowing air into the little optics hole to dislodge the dust works for me. If the pointer is not moving at all, I unplug the wireless receiver from the USB port it's plugged into on the computer, and wait until Windows makes the sound it generally makes when USB peripherals are disconnected. Then I plug it back in, the computer reloads the mouse driver, making another sound, and the mouse works again.
Neither of those may work for your situation, but they're easy to do and may be worth a try.