|Here's the problem I'm having...|
You appear to have 2 user input cells, E5 and D12.
You have asked for a way to increment E5 automatically until D13 > 0
My concern is that the manual entry in D12 could be such that D13 will never be > 0. I guess that's something that you will need to deal with.
That said, are you aware of the Solver feature?
Solver can be found under Tools. If it's not there, you'll need to add it via Tools...Add-ins. With the Solver, you can set up models and have Excel try to find the value in a given cell that "solves" your model. That might be better than using a macro.
If all you want is a macro, then this code will increment E5 by 1 each time through the loop and keep checking D13 until it is greater than 0.
As written, it only tries from 1 to 100, but that is easily changed.
For myNum = 1 To 100
Range("E5") = myNum
If Range("D13") > 0 Then
MsgBox "D13 equals " & Range("D13")
MsgBox "No Solution Found"
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