Help with FINDWINDOW, please...

I'm just moving from Clipper to Delphi, and trying to grasp the PCHAR concept.
I've written a program that is trying to locate an existing instance of an
application, but it doesn't work. Here is the important bit...

______
procedure TForm1.Button1Click(Sender: TObject);
VAR
KEITH:INTEGER;
findit,classwhat:string;
begin
classwhat:=#0;
findit:='File Manager'+#0;
KEITH:=FINDWINDOW(#0,(pchar(@findit[1])));
button1.caption:=inttostr(keith);
end;
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I always get 0 as my result. HELP!!