[kcal63]

Your problem is almost certainly a simple setting change in windows. USB slots are turned off to save power after a certain time by default and Windows, particularly win 7, is prone to lock from misread or misdirected wake function signaling. Find someone familiar with windows settings and registry (or research it yourself) and set USB power saving to 0, (off). This can be done for specific slots through editing the registry or changed for all through windows settings. Try that first, after making sure that batteries are good and mouse wake function is itself working (when you first try to restart using mouse do you see the light or not, don't look to windows till you are sure mouse function is good first). Hope this helps.