In EXCEL 2007 take the following actions:-
1. Click in cell C3 (for example)
2. Insert / Illustrations group / Shapes / click on Line / draw it in cell
C3 / DrawingTools group / Format / Shape Styles group / Shape Outline / click
the colour that you wish to have for the line.
3. Repeat step 2. for your second line but change the last step to a
different colour.
If my comments have helped please hit Yes.
Thanks.