Something different, now: When I first open this workbook, I can drag and drop rows on 5 of the 7 worksheets, but not on two of them. As soon as I save that workbook, I can no longer drag and drop in ANY any of the worksheets.

This contradicts some of what I wrote before, but if you ask me whether I was wrong before, or the behavior changed, I can't be sure. What hasn't changed is the basic problem: When I try to drag a row or column to a new location, it all looks normal as far as the point where I drop the cells, at which point the screen flickers (as though it momentarily went into the new situation) and the row or column reappears where it started.