I use and read these boards regularly and have gleemed great info in the past
so I hope someone can help me with this seemingly small problem that is very
stubborn.

I have a spreadsheet that I send to clients for them to use for their
billing. It has 3 tabs that have certain cells linked from the main tab to
the others and general cost information on the main tab. All data entry is
done on the main tab.

When I try to do a basic SUM formula for the rows above (formatted as a
number), instead of automatically highligting (like it has done for the last
15 years in in my experience) at least one cell above or to the left of the
cell that will contain the formula, it gives me =sum( ) and when I select the
cells I want to include it inserts the cells into the formula and gives me
0.00 as the result rather than the actual number. This happens no matter
what the formatting and even if I drag the formula from a cell that has it
working properly.

Thanks in advance for any information.