My 4s keeps locking up

Even after upgrade to 5.0.1 I'm still getting a phone lock up problem.

Black screen and pushing any buttons has no affect.

The only way to get it going again is to re-boot phone (power and home button for 10 sec)

When it re-starts, the Wi-Fi will not work, (greyed out saying "No Wi-Fi")

Then you have to reset network settings to get it to work.

I noticed today after 1st re-boot, if you re-boot again it will restart with Wi-Fi working again !

Saves the network setting resetting.

Any input on this would be apricieted.