I've made a bar chart with horizontal bars (the Y axis running from left to
right as you look at the screen). I would like to convers my second series
from a bar to a line, but whatyever I do Excel seems to create it on a
secondary Y axis that is vertical. When I go into 'format data series' it
won't let me plot it on the primary axis as the whole thing is greyed out.

Can anybody help me? I'm working in Excel 97 by the way.