row and col ref are all num how can I get it back to letters?

[Julio]

in excel 2007 my column and row references are all numbers all of a sudden.
How can I get the column references back to letters?

 

[Sheeloo]

To turn R1C1 referencing on or off in Excel 2007:

1. Click the Office Button.
2. Click Excel Options.
3. Switch to the Formulas tab.
4. Click the R1C1 reference style check box. A filled box will enable R1C1,
a cleared box will disable it.
5. Click OK.