I'm having a weird problem. I'm simply trying to do a conditional format on a
row, for example: If the value of cell A1 is 100, then highlight cells B1:B5
with yellow.

I go through to motion of selection B1 through B5, select conditional
formatting, enter formula as =A1="100" then select highlight color yellow.
The format says "Applies to =$B$1:$B$5", but when the value of A1 is 100 it
only highlights ONE CELL, not all of the celss that it is supposed to apply
to. It seems to highlight only the first cell and not the rest.

I have opened a new file and done just this one task and it continues to do
the same thing.

am I missing something stupid? I've been up for 20 hours.

Thanks