How do you stop excel from incrementing your variables during pasting

Hey guys using Office 2010, how can I make a variable stay static, even during a paste across multiple cells in a row? By design Excel increments the variables in a given formula, which usually works great, but what about those times, when you don't want it to, or not all the variables in a given formula?

Here is my basic formula:

=Details!H7-E17

I'm just trying to get the difference between E17:AP17 from Details!H7, but Details!H7 keeps incrementing when I paste it to the proceeding cells adjacent. How do you override this, and only during this particular pasting event? Now the E17 I do want it to continue to increment as normal, but the first variable H7, needs to stay H7.

If that is easy enough for you guys, then to add to that, H7 can be larger or smaller than E17. I just want to get the difference between the two, without getting the dreaded negative response if H17 is smaller than E17.

I think that is pretty clear, if not let me know.

thanks