Preventing users from selecting a cell in a range

I'm pretty new to macros so bare with me.

I have created a macro to ask the user to input a cell reference and then the macro inserts a row at that point and copies the formulae from the row below.

I want to modify the macro to prevent the user from selecting any cell in rows 1 to 21.

How do I do this?

Thanks

Thanks for the prompt reply.

I'm not sure that your proposed solution will work in my situation. I already have protection switched on and a large number of cells locked. When the macro runs it switches off the protection and then asks the user to select a cell.

If I have misunderstood you please could you re-post your solution with comments so that I can understand what it is doing - I'm very new to this.

Thanks