Opera 40 runs on Chromium 53.0.2785.101. I don't install flash but found these recent posts regarding XP and Vista. https://forums.adobe.com/thread/2209983 There is an issue with Flash Player on Opera on Windows XP/ Vista. https://forums.adobe.com/thread/2208589 XP/Vista: Flash PPAPI plugin 23.0.0.162 doesn't work in Opera and Chromium