I have a similar problem to the guy who posted earlier today--mouse is frozen, wireless signal strong, batteries good... I upped from 5.0 to 5.2 a couple of months ago. Oops. Began getting 2 error boxes on startup about a month ago. First: "Intellimouse has encountered a problem and needs to close..." Second: a Microsoft Visual C++ Runtime Library box which says: "Runtime Error! ...point32.exe..." and then the mouse would work fine, so I foolishly ignored the issue as I am swamped (also clueless, obviously), and the mouse still worked fine when I closed out these boxes. So last night the mouse just froze. Lights were on, solid, pushed all the buttons on both mouse and receiver. It was not listed under Devices in the Hardware tab in Mouse Properties. Uninstalled 5.2, reinstalled 5.0 from CD, restarted, now recognized in Devices, used Troubleshooter, no red flags, but continued not to work. Very frustrating search for help on web led me search the Knowlege Base, and then finally to here, and amazingly a post below appeared this morning with nearly the identical problem, but I decide to start a new thread to keep things clear. Question is: Do these error boxes constitue a serious problem, unfixable--like a "hardware failure"? Do they possibly indicate a more serious problem with my machine? By the way, I have screenshots of these error boxes with the "Error Report Contents" and the Error Signature sub-boxes in case anyone could use them to diagnose... I have xp, sp1, on a very clean machine. I am pretty computer illiterate (I am faking it). Please advise, or tell me to return the mouse to Costco if they'll take it. thanks!