X axis changed to numbers instead of letters. How did this happen and how do I fix it?

[gregnier]

Hello Forum,
I live in Fremont, Ca. and use Excel 2007.

Alarmingly, the "X" axis changed from the traditional format A, B, C, to 1,2,3, the same as the "Y" axis. This is not a chart but rather the entire horizontal "X" axis. I've used Excel for many years and never experienced this before.

Is this a "feature" of Excel 2007 not well known? If so, what good is it? How do I return the coordinate system back to the traditional format? That is: Horizontal axis, A, B, C. Incidentally, all the coordinate calls in all formulas were "transformed into a strange format: For example: "A1:P1" changed to: "R1C16." Both formulas reference exactly the same set of cells.

Please help,
gregnier

[shg]

Options > Formulas, untick R1C1 reference styles