I am trying to accomplish the following with no luck:

If cell A1 is "not blank" I would like cell A3 to have a red fill. When
anything is entered into cell A3, I would like it to then have no fill.

My spreadsheet is used to track steps of a project and this formatting would
cause all of the cells (steps) to go "red" when a new project was entered.
As steps were completed (data entered in the cell), the cell would then no
longer be red. Any red cells left would mean something still needs to be
done.

Thanks for any help,

Dave