I upgraded from Ubuntu 11 to 12.04, today, and everything seemed to go smoothly up to, and including the reboot. However, I now find that my mouse and keyboard no longer function, so I cannot login or otherwise use my computer. I have read other posts on this topic, but most of the answers seem to require the use of a keyboard to implement the solution--and I can't use my keyboard! I downloaded a 12.04 LiveCD and tried booting from it, but I have the same issue with that--no keyboard! My systems is a Lenovo with an AMD64 dual processor, and my keyboard and mouse are USB attached and shared with two other Windows PCs via a KVM switch (so I no the keyboard and mouse work!). I would appreciate some hints about how to make this PC usable, again. Thanks!