If you paste your exact formulas, I can probably provide more spedific help.
From what you've written so far:

You don't need a rule for <OR(A1,B1). I interpret your intention here to
be that if the cell value isn't equal to either A1 or B1 it doesn't get a
format.
If you don't set a rule, it simply won't apply formatting if the cells
aren't equal to A1 or B1 (the contents of your other two rules), which seems
to be what you want.
OR(A1,B1) will always return the logical value TRUE, which no number is
equal to.

If you want to apply a special format to cells that are not equal to A1 or
B1, if your range begins at A2, to apply this rule would look something like
(using the formula rule type):

=AND(A2<$A$1,A2<$B$1)

You must use absolute references on =A1 and =B1 or the value would update.
If your format range begins at A2, =A1 in a conditional format will check the
value of the row above each individual cell when applying the format and =B1
will check one row up and one column to the right.

"Bob Myers" wrote:

Need some help. Just switched to Excel 2007 and things seem to be
different.

Have a Range of cells of about 20 x 20. Two other cells, A1 & B1, have
numbers in them.

My conditional formatting is set up such that if any of the cells in the
Range = A1 it gets filled with one color, if it = B1 it gets filled with
another color, and if it < OR(A1, B1) it gets no fill color.

Nothing happens when I change a value in either A1 or B1. But if I switch
to another Tab and then switch back, the conditional formatting is correct.
What am I missing?

Respectfully submitted,
Bob Myers