For a new chart, fix the data first. Put the X values in the first column
and Y values in the columns to the right. Put a label (series name) in the
row above the first row of data for each set of Y values, but keep the cell
atop the X values blank. Select the entire range, including X values, series
names, and blank cell, then start the chart wizard. The blank cell helps
Excel interpret the data range.