Thanks for the links.
I finally solved the problem of "finding" my music in PowerAmp. I went into settings and checked off all options for seeking music, then did a re-scan for music files. It seems to have found all of them, plus other sound files. I'm going to have to figure out how to get the sound files that aren't music out of the queue now (like the chiming and beeps from my GPS). I think I prefer PowerAmp mostly for its very comprehensive EQ, including the preamp. Although PlayerPro does have advantages, too (it found my music easier this time, without having to do a rescan or getting sound files that aren't music).