I had a similar issue; my mouse cursor sttarted to move on the screen, when I was not touching it. All on its own it would start moving. Annoying when I was trying to complete an email or Word doc. I changed the mouse batteries; no difference. Over the course of a week, it got progressively worse. This is in an office, and I called our tech support, who did not know what to do! Finally the cursor was moving around even before I logged in (control/alt/delete). That was the point at which I had a thought; it looks like someone else is moving my mouse! Aha, who is in the office? I checked with them, asked them to move their mouse and hey presto mine moved too!
We both have a Microsoft Wireless Optical deskset, with mouse and keyboard. The signal from my colleague's mouse had changed to exactly the same frequency as mine, hence the loss of control at my end. Once we reset the Receivers, all reverted to normal, problem solved.