Bluetooth mouse problems

I have recently purchased a bluetooth mouse for my hp vista laptop. The mouse
installed fine and works well. However when i shutdown the computer the mouse
shuts off the optical light as though it has switched itself off. when I
reboot my computer the only way i can get the mouse to work again is to take
out and put back the bateries in the mouse search via bluetooth and reinstall
the mouse. Any help would be greatly appreciated.