I stepped away from my Latitude E6410 (running Windows7) and returned to find it locked as appropriate at the usual screen asking me to "Press CTRL-ALT-DEL to unlock this computer."  But CTRL-ALT-DEL doesn't work, nor any other keys, so I can't log back on.  The mouse works, and I can even bring up the On-Screen Keyboard via the Ease-of-Access button, but that hasn't helped, even with Sticky Keys activated.  Rebooting just brings me back to the same screen requiring CTRL-ALT-DEL.  And yes, we have a new cat, so I suspect he pressed a key too long or somehow managed an unfortunate combination.  Any ideas?  Regarding the computer, that is, not the cat.