Over the last few days my cursor has been stalling and jumping all over the shop. I noticed the battery light was flashing and thought that had to be it... But no, I installed new batteries and there is no change. I've uninstalled and reinstalled the mouse, made sure the drivers were current, and stopped and started bluetooth in services. The only thing that's changed in my house is the installation of a new router. I switched to tethering on my iPhone and it was still doing it... Could it be that just something with the router in the air is affecting my mouse? I can't actually turn it off for 10 days which is annoying, but EE are 'conditioning' my line, whatever that means. I'm beginning to admit defeat and consider that the mouse is actually broken. It's only about 3-4 months old but the problem is I (think I) bought it from eBay. But you cannot search beyond 60 days I have no receipt... I've never returned anything to Microsoft, would they accept it if there was a problem!? I've managed to get my hands on a USB bluetooth receiver so I'm going to chuck that in my old computer tonight and see if it goes wrong on that one too.