Please say more. Your original words are subject to various interpretations.

There are 21 quarters from 2001 to Q1 2007. A line chart has no difficulty
displaying much more than 21 x-categories in a single series. Also, a line
chart has no difficulty displaying much more than 21 data series.

Particularly puzzling is your statement that it "erases all the data for
that particular series". If you mean that the worksheet cells are emptied of
data, then there is likely a macro running behind the scenes that is doing
the deed.

Jerry

"lisa721" wrote:

I have Excel 2000 and am have a line chart with quarterly data from 2002 to
now. When adding the 1Q07 data to my chart, the computer won't accept the
new cells and erases all the data for that particular series. I've tried
starting over with the same results. Any suggestions to get around this?