Macbook Air Running version 10.7.5 won't connect to wifi but connects via Ethernet I have a MBA and I have connected to my home network before. I went on holiday and on return, I cannot connect to Wifi anymore.

It tells me "connection time-out occurred". But my Ipod Touch (4th Gen) and Samsung Galaxy S2 can connect to the home wifi network and everyone else (I live with friends) has no issues with the wi-fi.

I already tried removing all the "Preferred networks" and tried to do an SMC reset on my Macbook Air. Nothing worked. I also went into Keychain and removed home network from there. Still not resolved

I then tried tethering my MBA to my Samsung Galaxy S2's wifi and I could connect and surf normally. (so I concluded nothing is wrong with my laptop's Airport/wifi utility)

Finally I decided to try and connect my MBA to the router via Ethernet cable, and I am able to surf and go online as normal

I updated all my software on the laptop and it is still not working. I can find my home network and click on it but when I input the password, it says "Connection Failed". I also tried setting up the network manually and inputting the password but again "Connection Failed"

I am unable to get into the router as I don't have the IP address for it. Does anyone else have a similar problem?

I have yet to try to connect to a neighbour's Wi-Fi but I will try that tonight.
Try resetting any proxy settings you may have enabled (go to System Preferences > Network > Advanced > Proxy)
Reset your router
Attempt to connect via WPS if your router supports it
Find the IP address of your router and enter it into the URL bar of your browser