New--cannot copy and paste

Just today, I find I cannot copy and paste in MS 3.2. I always, for years, use the header selection to put the title on the top of each page after the first one. I type in the title, complete with the $:tag:songnamexxxx in the first [odd] box, then highlight it, hit ctrl-C, start the cursor in the second [even] box, hit ctrl-V. For years this works flawlessly. Today--not.
I then wrote a couple bars of music, highlighted it, copied, then tried to paste into another part--not happening. I've tried just using the copy and paste tab under "edit"---nothing.
I then did a copy and paste outside of MS, just in my word program---no problem using either way.
I can now assume that it is not my keyboard getting wonky and that all other functions on my computer still function correctly, outside of musescore.
Please, any suggestions?
scott