Why is my header row numbers instead of letters?

[raula]

The standard header row used to be letters (A - B - C) and the left column
was and still is numbers (1 - 2 - 3). When I logged in today, my standard
header row is now numbers (1 - 2 - 3). If I need to create a formula it's
now 11 or 12 instead of A1 or A2. How can I change this back to letters?

 

[Dave Peterson]

In xl2003 menus:
Tools|Options|General Tab|Uncheck R1C1 reference style

 

[Gary''s Student]

Tools > Options > General > clear the R1C1 checkbox