Your PRV is fully zoomed out, try zooming in using the zoom buttons in the bottom right hand corner or left click and drag in the top half of the timeline ruler in the PRV.
I repeat, rather than frustrating yourself and blaming the software, learn how to use it properly by running through the tutorials in the manual (or buying yourself one of the excellent tuition videos available

).
Whichever software you use you'll need to do that. It's a complex software program not a text editor..... i.e. there is a learning curve involved.