Tools/Options/General, uncheck the R1C1 Reference Style checkbox.

In article ,
"Measurement Consultant" <Measurement
wrote:

The column headers are displaying numbers (1,2,3) instead of letters (A,B,C),
which is making it difficult for me to type in formulas. Ultimately, I'd
like to have a column at the right end of my spreadsheet that totals a
specific set of columns *within each row*. How do I do this?

I am using Excel that came with Microsoft Windows XP