Function keys not working

My top row of keys (function) seem to have either stopped working or changed function. Volume keys (F7 - F9) do not work. Brightness keys (F4 - F5) do not operate brightness but bring up the internet search box and page function, battery key (F3) moves cursor to Find field, Wi-Fi on/off (F2) and Screen selection (F1) appears to do nothing. F10 - F12 keys move the cursor around the screen and opens up a toolbar.

All other keys on the top row (other than Function) appear ok.

Any thoughts?

Thanks