The "U", "M", "J", and "7" keys do not always work-sometimes they print themselves more than once or sometimes not at all and sometimes they will only print if the "caps lock" key is on!
How can I solve this problem?

Jan, May 2017

If you munch cheese rolls while you type then bread crumbs fall on the keyboard and mess up the action of the keys.

One solution is to remove the key cap and to clean out the debris with a soft brush. Refitting the key caps can be a bit fiddly.

https://www.youtube.com/watch?v=QCYOiK9QP08

Good Luck..., May 2017

They need a good clean under the keyboard or buy a USB external k/bd

roger, May 2017