anyone good with excel '07?

Can you post the spreadsheet or the formulas you are using? That would make it a lot easier for people to help.

I'm sure there is some way to do it in Excel, but I can't say I know off hand. Here is how it is done mathematically:

Take your two equations for each line/curve. Let's say you have

y=3x+7 and y=-2x+4

Because you want the point at which each line intersects, you are looking for the same value in x & y for both equations. So we can say this:

3x+7=-2x+4

So you can solve for the same x value. Once you solve for x (here, x=-0.6), you can solve for y in either of the original equations, and then you have your x & y at which the two lines intersect. In this example, you end with x=-0.6 and y=5.2. You can follow the same method for more complex equations, too, like parabolas, but in that case, you can have more than one intersection point.