Hi

In excel 2007, when I add a trend line to some data to which has
negative x values it always extends the trendline to x=0.  This is
quite annoying, does anyone know why it does this or have a fix for
this?

try plotting

-2    -1
-2.1    0
-2.2    1
-2.3    2

and adding a trend line.  I've not used the forecast options so I
wouldn't expect it to extend the trend line.

Any help much appreciated.