If the main deco works in router mode, desktop gets IP address from Deco. Then you need to open ports for the desktop on deco first, then open ports for deco on your main router. But if you set up...

Range extender can only connect to normal wifi, may not compatible with hotspot or hotel wifi(which may need portal authentication). Tested with my hotspot before, no luck. Maybe you can try with...

What's the model? If WPS fails, can try web UI, refer to this guide: http://www.tp-link.com/us/faq-930.html

What's the model number of your router? There is wireless password already for the wireless connection, which is usually printed on the back of the router, or can be found on the info card. There is...

Make sure the system time is set up correctly. And after your re-enable the parental control, reboot the router. There may be some delay, but shouldn't be hours or days. If the problem persists,...

what if you set the C9 as a regular wireless router? would it make a difference? maybe update the firmware? not sure if that helps, but give it a shot.