Files from Windows 7 are not alphabetized correctly on OS X, and can match identically named files in the same folder

Question

I receive MS Word files from students using Macs or Windows-based computers.  This year, files prepared by students using Windows 7 are not alphabetized correctly on my Mac (under Snow Leopard or Mountain Lion).  The same four students keep having their files put at the END of the alphabetical sort by name, even though the files should appear earlier in the list.  I have to copy the file contents and paste the contents into a new document to get the new document to appear in the right order, and if I do so, then BOTH the old and new files appear in the Finder, even though the names appear to be identical!  So can have to files with the same name in the same folder, which ought to be impossible.  Does anyone have any idea what's going on?

Answer 1

Bingo! 
The problem is not the letters themselves, but non-letter characters in the file name; this showed up with the fixed-width fonts. The apparent duplicates and mis-sorting are caused by dashes, which differ because they're done as en-dashes in one file name and em-dashes in the other file name, or by curly or straight apostrophes.  I didn't see that in the Finder window.
I never saw this behavior before this year.  Last year, when I was using a Mac for the first time, I did not see any such problem, even though my students' files were named using the same conventions. When I was using a Windows-based laptop before that, I never saw the problem.
Windows must do something to style the non-letter characters differently than a Mac.  Is there any place in Windows Explorer or the OS X Finder that styles characters this way?  I can see this being a big problem for someone who needs to sort very important data by name, when the files are coming from different operating systems!
(I just Googled en-dash, em-dash, and curly quotes with file names, and found a good number of posts on various sites about similar problems based on ASCI character coding, html coding, Windows Explorer, and other applications.  Sometimes the files don't appear at all, because the application reading the file name can't deal with a certain ASCI code.  What a mess.)