Savoir si Internet Explorer est installé

uses registry;

function IE_Installed : Boolean;
var
Reg: TRegistry;
s: String;
begin
Reg:=TRegistry.Create;
With Reg do
Begin
RootKey:=HKEY_LOCAL_MACHINE;
OpenKey('SoftwareMicrosoftInternet Explorer', False);
if ValueExists('Version') then S := ReadString('Version')
else S :='';
CloseKey;
Free;
end;
if (length(S)>0) and (StrtoInt(s[1])>3) then result:=true else result:=false;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
if IE_Installed then
ShowMessage('Internet Explorer installed.');
end;