Call them and see if you can blag a new one under tech support. Tell them its just stopped functioning and you know its the receiver because you tried it on someone else's and it was fine. I've no time for companies taking the mick like that when they often replace very expensive things for free without proof the fault is theirs. MS used to send me a new mouse / kb as long as I gave them the serial number on the unit.Forgot the dongle for my MX Revolution was in the front of my machine while moving it and managed to snap it in two
Was expecting new dongles to be a couple of quid from that auction site but the cheapest I've seen is £25... for just the dongle
Now using some crappy Dell wired thing as it's the only mouse I had lying around.