Find and replace Loop Error

I have the following code in my macro and when I run the macro it always freezes at this code, I think it loops it.. What's wrong with it?

For Each c In ActiveSheet.UsedRange
c = Replace(c, "userfield", "LT REM")
Next
End If

I also have this code which finds the last column then it inserts 2 columns named donors, and cost. The column heading starts at row 5. But it dont work.

Lcol = Range("IV1").End(xlToLeft).Column + 1
Cells(5, Lcol) = "Donor Net Rev"
Lcol = Range("IV1").End(xlToLeft).Column + 1
Cells(5, Lcol) = "Cost/Donor List"