Wow. Thanks for the quick responses and for not making fun of me for using a 15 year old DAW!?
So the first time this happened I did "edit-bounce to clip" and it brought the wav file back. But that no longer works. I tried what Mark suggested. In Sonar 6 it's "process-audio-gain", but that did not work. I had previously tried clearing the picture cache and that didn't work. And I can't find anything for redrawing waveforms in this DAW.
Like I said, I uploaded files that I recorded on a Tascam portastudio and the wav files showed up flat. So I did "edit-bounce to clip" for each track and the wav files showed up. I spent about 3 hours editing and mixing with no issues. I closed the program, got some dinner and when I came back and reopened is when the problem came up again and the "bounce to clip" thing I previously did would no longer work.
I tried recording something straight into Sonar instead of pulling in previously recorded tracks and it was the same - getting sound, but no visual wave.
I actually downloaded Cakewalk a few months ago and like it better than other DAWs I tried (Reaper, Studio-One, Ableton), but I still prefer Sonar. I do all live instrument recording and I love the straightforward simplicity of it. The layout is clean and easy. I can work quick on it in terms of comping and editing takes. I like the sonitus EQ. It's everything I need in a DAW!
I did open up the Sonar file in Cakewalk and everything transferred in smoothly and plays just fine. I'd prefer to stick with Sonar, but at least I know I can still work on these.