Hi, I am trying to set up conditional formatting in a particular cell
-- what I want to do is have the cell turn gray if 2,000,000 divided
by the value in the cell is less than 0.35.

One way is to use
Format Conditional formatting
Cell value is greater than 700000


... Also, I want to
apply this conditional formatting across multiple cells

This conditional format can be copied using the "format painter" brush.

(I have Excel 2003.)