Interference can sometimes play a part in this. The phone will connect but it will "wait its turn" to send and receive data, check if it will connect and transfer over a different wifi network. (starbucks, etc.) If not then you may be stuck with the hard reset, I assume you already deleted and readded the wifi network on the phone.
Interference can come from a microwave, cordless phone, (worse yet, a neighbor's cordless phone) or in my case it is from my Samsung wireless surround sound. Took me a long time to figure it out, but as soon as I turned off the surround sound my laptop, thunderbolt and PS3 all connected and worked flawlessly. Prior to figuring it out they would all show connected with great signal strength, but would not work. (this really sucks on the PS3 where I would like surround sound during Black Ops sessions, but can't have both)
I have been told that a duel band router may fix the problem. But haven't tried it yet.
Good luck.
