If everything in Device Manager and the wireless settings is fine, and it still doesn't work, the next step is to try a USB dongle to connect wirelessly, in stead of the built-in WiFi hardware.
So, I am back to my parents for some time and I can't connect on their wifi. In my apartment I was using LAN cable and internet was working fine. Here I wanted to use wifi, because my room is too far from router. When enable that type of network and try to connect I get message that Windows is unable to connect (signal strength is very good - 4 of 5). Than I moved my pc just to try with LAN cable and it is working correctly. When I try to use wifi and I go to device manager it says that Wifi adapter is working correctly.
Also I have to say that I was using wifi adapter before when I was coming to parents and everything was working good before.
Also at the same time I have another problem. When I have enabled wifi adapter and I start my laptop, monitor after maybe 10 seconds goes to sleep. So, monitor goes to sleep before windows is started.
For me is not logic to this 2 things are connected somehow, but problems started at the same time and only when I try to connect via wifi. When I am using LAN, laptop starts and reboot normally.
I hope that someone have some idea.
I also tried to reset router, restart router, unplug router, and that is not working.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic