I am using the TP-LINK TL-WN781ND and can't access the internet. It started about two days ago and everything was working fine, then I couldn't connect to my network, which shows up in the network and sharing centre. My IPv4 and IPv6 obtain ip and DNS automatically and I do not know what else to try. Any further details you need I will try to provide.
* Is the internet working on other devices (computers/tablets) with wired or wireless?
* The TP-LINK TL-WN781ND is the wireless card in your computer, what is the wireless router's brand and model?
* What version of Windows ?
There are steps you could try below, I am assuming you are using Windows 7, and the rest of your setup is working fine, and that there aren't issues with the wireless router you are using or the internet service provider you are getting internet through.
if you are unsure, try calling your service provider to get assistance first, otherwise this will be working across purpose with any assistance they could be providing you. Also it is typically easier to solve over the phone.
and if you haven't already done this, shutdown and startup again (not a restart).
If the SSID or Pre-Shared keys have changed this won't work.
if you have the Pre-Shared key (wireless password) and know the SSID (wireless routers broadcasted network name).
step 1 - go into network and sharing center.
step 2 - click on manage wireless networks. (wireless profiles).
step 3 - see if you can find your SSID and remove it.
step 4 - back into network and sharing center.
step 5 - click on connect to a network.
step 6 - find your SSID in the list provided and try and connect.
step 7 - enter your Pre-Shared key and connect.
all this does is connect your computer to the wireless router, the same as if you connected a cable from your computer to the router. It does not solve issues with the wireless router and or the internet provider.