you don't need to be an top programmer, you must want to learn, and try to understand. this is a very simple task which could be done if you took a delphi book, and try to accomplish it

code:
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
Label1: TLabel;
procedure Button1Click(Sender: TObject);
private
function prime(number:integer):string;
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
Label1.Caption:=prime(strtoint(edit1.Text));
end;

function TForm1.prime(number:integer): string;
var i:integer;
prime:boolean;
begin
Label1.Caption:='';
prime:=true;
result:='prime';
if (number=1) or (number=2) or (number=3) then prime:=true
else
for i:=2 to round(sqrt(number)) do
if number mod i=0 then
begin
prime:=false;
result:='not prime';
exit;
end;
end;

end.

hope you'll try to understand this program, not only to copy it and past it.

best regards,