It looks like you're new here. If you want to get involved, click one of these buttons!
Use the wired mouse?
Get a UPS?
I assume that you've tried rebooting the computer and replacing the batteries.
some older wireless mouse would have corroded contacts for battery. sometimes you need to take a peice of sandpaper and clean out the oxidation from the battery contact points. aside from that... you can try redownloading the mouse driver and reinstall the driver. maybe it got corrupted?