How do I disable the Help F1 key?

For 12.10

You can disable the help browser by opening "System Settings" -> "Keyboard" and switching to the "Shortcuts" tab, then under "Launchers" turning "Launch Help Browser" to "Disabled".

However some applications, for example the terminal, have their own help settings you will have to turn off as well. For the terminal, open the "Edit" menu and click on "Keyboard Shortcuts". Scroll to the bottom and change the key for "Contents" under "Help". To turn the shortcut off, select it and then hit backspace.

14.04

Install the DConf editor, go to org > gnome > desktop > wm > keybindings.

Assign the F1 key to some inoffensive function, like 'raise'.

You can go into Settings->Keyboard->Shortcuts->Starter and press backspace on the coressponding item. Sth. like 'Launch help'

However other applications might still open their help on F1