call RegQueryDWordValue to get office Excel Version using inno Setup installer

How do I get installed Version of MS office Excel from registry using inno Script? i tried bellow code,But not working…

function InitializeSetup(): Boolean;
var
CurVer: Cardinal;
key: string;

begin
if RegQueryDWordValue(HKCR, ‘\Excel.Application\’,
‘CurVer’, CurVer) then
begin
// Successfully read the value
MsgBox('Excel Version: ’ + IntToStr(CurVer),mbInformation, MB_OK);
end;

end;