If you have set the Stream dropbox to 'allow other devices..." and they still won't stream, you either have a faulty device driver or you have corrupt system files. I would uninstall and reinstall Media Player, and the Media Center. There are checkboxes for that. Click Start, and type 'turn windows features on and off'. You need to uncheck, apply, restart windows, recheck, and apply, restart again.
Rating posts helps other usersMark L. Ferguson MS-MVP