Iphone 4s - wifi grayed out, but has MAC address Solution

I got it working for a while when I did the following:

1) Turned it off

2) Sealed it

3) Put it in the freezer for 15 minutes

4) Turned it on

At that time wifi was enabled and found my wifi access point, to which I could connect.

After a while , the access point was not found anymore, and could not find other access points.

At that time I could switch off wifi, and turn it on again with the slidebar.

When I rebooted the iphone, I could not enable wifi anymore.