cutting in Audacity [SOLVED]

My curser won’t let me highlight required parts of a song to edit/cut
I’m in stop mode but when I choose a particular part of a song to edit, the ‘line’ moves to another part.
Can anyone help, please?

Check that you haven’t accidentally enabled “Snap To” http://manual.audacityteam.org/man/selection_toolbar.html#snap

Wow!! Thanks so much - ‘Snap to’ was on ‘nearest’, changed to ‘off’ - working great now