Are you adding one cell at a time, using Ctrl+click? This is a fragile way
of adding data. The best way is first to make sure the data is in a
contiguous range (no blank rows or columns in between data for adjacent
quarters), then stretching the range to accommodate the new values. When you
select a series, the source data is highlighted with colored rectangles, and
these rectangles can be manipulated with the mouse to change the source data
of the series.

- Jon
-------
Jon Peltier, Microsoft Excel MVP
Tutorials and Custom Solutions
http://PeltierTech.com
_______


"lisa721" wrote in message
...
The data is not erased from the worksheet; it disappears from the value
field
in the "Source Data" box. In the "source data" box, when I click to add
the
cell with the new data, all the previous data in the field is gone. I am
not
using macros; the line chart displays 3 series with the dates listed on
the X
axis. I hope this clarifies your questions.

"Jerry W. Lewis" wrote:

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?