My wifi connects but says limited and wont access the internet?

[cjcraner]

My wifi says no valid ip address. What does this mean?

 

[Emerald]

it means it was not able to authenticate/communicate to the router and did not receive an IP from the router

 

[Marysus]

it means it was not able to authenticate/communicate to the router and did not receive an IP from the router

Okay,so do you know what one should do next? And how? I'm rubbish with computers but would like to fix this,but i've no idea where to even start... Thank you