This problem happened out of the blue. My laptop will no longer connect to my wireless access point (it won't connect at my college either). It sees my connection in the 'connections available' menu with full bars, and when i click to connect, it does the loading blue circle thing, then says unable to connect. I haven't had internet access for a few days now on my laptop which is kind of a problem, especially at school. I know its not my connection or the router because my desktop pc, ipod touch, blackberry, and xbox live are all connected to my access point perfectly fine with no problems.
I have the latest drivers (my laptop is brand new.. i ordered it February of this year), I have it set to detect an IP automatically.. I just don't understand what the problem is. Before hand.. there were a few times here and there where my signal would completely drop out of nowhere and I'd have to restart my laptop, then I would be connected again. This time, I turned my laptop on to no connection and after countless restarts, I still can't connect to my access point. The router is upstairs right above me. I've tried taking the laptop upstairs right next to it, and it still won't connect. What is wrong with it??
I would delete the wireless networks from your preferred list and try again. Keep in mind that deleting yoru wireless networks will require you to re-enter your network passwords. You can easily locate them by going to "Network Sharing Center" and then clicking "Manage Wireless Networks".
I know this is 2 years later but wanted to thank Gabez for this advice. After I'd spent hours trawling through all sorts of convoluted "solutions" for reconnecting the M11x to a wireless network, with suggestions like "Reinstall the chipset" or "Take the back off of your machine and mess around with the stuff inside" it was GabeZ's answer that was the best.