I have a Lenovo B50-50 laptop. Lately it has had a mind of its own, when typing, some of the letters haven't appeared after I've looked up at the screen after a few seconds, so I had to go back and hit them again sometimes a few times.\nA Google search suggested turning the laptop upside down and shakng it, then vacuuming the keyboard. Must be a common fault, to have made its way onto "Computing Net" message board.\n\n\nThis didn't work.\n\nSo I gave the keyboard a good spray with Servisol switch cleaner. The stuff I use on my jukeboxes. This did the trick.