When connection drops, how about status of ADSL light and Internet light on W8980? You'd better ask your ISP to check if they made some limitation on their end when you use a brand which is not given...

Follow the guide as below to restrict the hours your daughter uses the internet. http://www.tp-link.com/en/faq-467.html

Internet light on the router is on? Other wireless clients and wired connection are all working? On the iphone, if you cannot access internet, can you login http://192.168.1.1 which is your router's...

Did you try chipmaker's driver? Contact TP-LINK support and ask for it to try. http://ticket.tp-link.com/index.php?/Tickets/Submit

What's the operating system of your PC, Windows 7? Try to enable WLAN Autoconfig and try again. http://www.tp-link.com/en/faq-306.html If it doesn't work, uninstall the driver, uninstall anti-virus...

Did you use POE injector in the package? How did you connect? PoE port on the injector is connected to LAN port of WA901ND and LAN port on the injector is connected to your router or switch?