uses
Registry;

Function DefaultBrowser(): STRING;
var
regist: TRegistry;
BrowserPath: STRING;
begin
regist:=Tregistry.Create;
regist.RootKey:= HKEY_CLASSES_ROOT;
regist.OpenKey('\http\shell\open\command\',FALSE);
BrowserPath :=  Trim(regist.ReadString(''));
regist.Free;
BrowserPath := Copy(BrowserPath, 2, length(BrowserPath));
result := Copy(BrowserPath,0, Pos('"', BrowserPath)-1);
end;