External mouse goes dead at some times

[wacian]

I have got an a4tech R7 PowerSaver usb wireless mouse, however some times when I leave the external mouse untouched, it doesn't work any more. The LED on the receiver which shows receiving radio waves also does'nt turn on (or just flashes when I keep clicking).
Whenever this happens, re instering the usb receiver will solve the problem, so does the system restart.
and moreover, is there any way to turn off touchpad when I connect the external mouse?

I've got:
T61
windows vista business