Disappearing data!!

I am compiling a set of statistics in an Excel file I received from another person. There are parallel columns of number entries (1, 2, 3, 4, or 5) and I have added enough more columns to spread out the data in table format--ratings 1 though 5 at the head of the five columns, and entering 1 in the appropriate column to register the value required, so that I can have sums of each rating at the bottom.

Everything was working well until I got to a row in which I noticed an oddly-skewed entry in the first cell, where the words seemed to break and slant in a strange way. When I tried to enter the "1" in the appropriate cell, it was there until I clicked elsewhere, in which case that "1" simply disappeared! I tried duplicating that row and deleting the offending one, to no effect. I have done my best to figure out the cause of the disappearing number, but I am thoroughly bumfuzzled. This is an important report I am working on, and I very much need this document to work properly.

I would be most grateful to hear some possibilities for alleviating my quandary!
Many thanks,
RESC

Thank you for your reply.
Actually, I solved the problem just now by inserting a blank row and copying all the data, cell by cell, from the faulty row to the blank row. Then I deleted the faulty row. Now it all works!
But thank you very much, anyway!