Suspect a corrupted measure

I'm new to Musescore, but I have read through as much of the forum posts as I thought applied & didn't find anything directly helpful. So, I'm hoping that someone can take a look at my attached file to see if there is something that can be fixed so I don't have to start over.

I'm using Musescore 1.3 with Windows 7. I created some of my file on another computer which had XP, but I don't remember which version of Musescore was on it (other than the fact that I downloaded Musescore to that computer within the last week) & that computer is no longer available to me.

I'm working on putting Lark Ascending into Musescore (with keyboard and mouse, not MIDI or anything similar) in order to transpose it for viola when I'm done entering it. I did a chunk of work today (most of the 3rd page), and it all looked great. Then, I saved it and closed it. When I reopened it (to admire it), the stems (and some other markings) were all gone from the 3rd page. If I copy a measure of the "bad page" and paste it in a later measure, it looks like it originally did while I'm looking at it; but if I save, close, and reopen, then the pasted measure is also missing stems and other things. From what I read on the support forum, I suspect I might have a corrupted measure, but I don't know enough to know how to find it. I tried copying and pasting the two "good pages" into a new file (piece), but there were some new troubles in the piece when I did that.

Any advice or help would be appreciated. I know I could just start completely fresh and do it all over, but I'm really hoping I don't need to do that!