Q: OSX Yosemite Wi-Fi: no hardware installed

Hi ASC:

I installed Yosemite about 2 weeks ago, and at first my wi-fi (at home & work) was working fine, but then about a week ago the Wi-Fi icon at the top of the toolbar got an "X" in the middle of it and when I click on the Wi-Fi icon it says, "No hardware installed". I tried resetting the SMC on portables with a battery you should not remove on your own (from another thread) but no luck. I've googled this, YouTube-ed it, but still no Wi-Fi back. Someone PLEASE help

I'm using:

OSX Yosemite

10.10.1

MacBook Pro (15-inch, early 2011)

Thank you.