Unable To Select

Hi, I’ve been using n-track for a year, and have recently run into a problem where I can’t select.

Usually I have very long wav files with several songs in them, and I have to cut them up. To do this I click and drag inside the wav files. For some reason I can’t do this anymore.

Any suggestions. I have 4.03, which I reinstalled after having the problem for a week, but that didn’t help.