From what you're describing, it sounds like you're going to hide column B and C in your finished worksheet. I say this because I assume you want to keep the full list from the user view and only reveal results for single entries. Therefore I will suggest a different approach.
I recommend using two different worksheets within the same workbook.
Sheet 1 : Contains data entry cell and lookup formula.
Sheet 2 : Contains complete list of pin numbers and names
If you do this then you can show the result of lookup in a different cell than the one used for the pin number entry. Obviously you would hide sheet two and protect the workbook with a password.
However, the above does not solve the problem whereby you want the result of lookup to appear in same cell as the data entry. You can do this using a macro.
In sheet 1, you have the lookup in a cell that is not the same as the cell where user keyed value for lookup. I would record a macro that copies value from lookup cell and then paste VALUE into data entry cell. Assign a button to the macro. Then hide lookup cell and protect sheet.
You should be Okay with these approaches as long as my assumptions are accurate. I don't understand the benefit of displaying a result in same cell as entry was. Maybe you could explain more about why you described it that way and then we could come up with yet another approach?
Hope this helps,
Kind regards,
QwertyKPH @ Yahoo!