Try this -
1. Expand the track that you are trying to work with so that you can only see it on screen and so that three bars of music fills all the horizontal space. Click on the track to make sure it is active.
2. Using the mouse, click and drag along the ruler, just under the bar markers to highlight the section that you want to delete.
3. Press delete. Only the highlighted section should go.
Make sense?
Also, in step #2, you could use the EDIT-SELECT BY TIME command to choose the range you want to delete, (or edit or copy etc)
Ciao,
Q.