Authentication required, cannot connect to wireless

[Esrak]

Hey everyone,

I honestly have no idea about ubuntu but somehow using it for sometime. I was just fine with it until it suddenly started to not connecting to the wireless connection that I use at home.
I'm using Ubuntu 12.04

Can anyone help me on this issue please?

[Moofus]

what all have you tried?

[Esrak]

Well I tried all the usual methods like forgetting the network I used to connect. But I think the problem is much more complicated.

[Moofus]

have you rebooted your router?
also just doing a fresh install of Ubuntu 14.04.2 would probably fix it.
what brand is your wireless card?