I have a dell Inspiron Mini and a TP Link router and it does not work (internet)... Can anyone Fix this :O :D TL - WR340GD V 2.0

Means no internet connection , better check the network connectivity properly.

Can you elaborate more on the type of device you are trying to connect to your WiFi or if every WiFi device you have is experiencing issues connecting to the internet?

Unplug it

After the router is plugged in what lights are on / stay on?

What lights are on and what lights are blinking? If you thnk it's a problem with your ISP, did you call them so they can diagnose their line?

Look for the sticker at the bottom of your router and get the WPA key.

Read here

Hello maybe the manual could be helpfull:

http://www.tp-link.com/en/products/details/?model=TL-WR340GD#down

You need a pdf reader (ADOBE) to read the content.

Good luck

Have you set the TP Link TL-WA901ND IP to have 192.168.1.1 as the default gateway ?
Also DHCP server is where ?
IN the TP LINK TL-WA901ND or in DLINK DIR 615
Only have one Router running DHCP and set the default gateway in the leases as 192.168.1.1.
What subnet mask are you using is it the same through out all devices ?

Press the reset button at the back of router for 20 sec to reset password