If you're pressing the U I O P J K L M keys and seeing numbers instead of letters, then the NumPad is enabled, and must be switched off to get things back to normal.
To disable the NumPad press:
Fn + Ins
If you're pressing the U I O P J K L M keys and seeing numbers instead of letters, then the NumPad is enabled, and must be switched off to get things back to normal.
To disable the NumPad press:
Fn + Ins