Chosen Solution
After that I changed the power button the wifi signal is very weak. So the problem is not software, but all the components are in the right place and I don’t think that the wifi antenna is broken because I didn’t touch it. Does anyone have any solution? Update (09/17/2015) I changed the wifi antenna. But I still have the problem
The most likely thing would be that the antenna cable is not fully seated in its connector on he motherboard. I would check that again.
