I have very strange problem with my USB mouse and keyboard:
Sometimes during normal work in W7 they became deatached (there is that funky sound of deataching device in W7), without any my ingeretion. They cannot be reatached until next reboot, even if I plug them out and then plug in (even in different USB slot). The mouse deatached still emit red light from under, but on screen cursor and mouse buttons are not responding. I can attach different mouse into some other port (and it's works), as I have second mouse and tried that.