I have an Excel spreadsheet that was created by someone else, but is saved on
my computer. Certain cells have always been shaded. My computer was just
upgraded, although my Excel version is the same. The shading is now gone
from this file (same file, transferred to the new computer), and I cannot
format any cells. The sheet is not protected, and there are no conditional
formats. If I format a cell (Say, for red font), new typing appears with the
new format until I hit return and then reverts back to original formatting.

Any ideas?

tia, kelli