MacBook Pro (Early 2011) No Wifi Hardware Installed

Question

Please help me! I'm confused.
My 13" MacBook Pro (Early 2011) Keeps saying that No WIFI Hardware is installed.
My Mac has been running great until earlier this week. I turned it off one night before bed and then the next morning as I switched it on, it said there was no WIFI hardware installed. I launched recover mode which is when I figured my WIFI works in recovery mode just not in the Mac itself. I reinstalled a fresh copy of OS X Yosemite which worked for a day, but sure thing the next day I loaded the Mac and then there was the same issue. So I reinstalled OS X Yosemite... AGAIN!! this time I hit an error, Yosemite had deleting my recovery drive and unmounted my Macintosh HD but thats anther story to fix another time. Once I finally repaired my disk to install Yosemite my WIFI was working again... until I restarted my Mac and it went off and the error reappeared. Luckily Apple released OS X 10.10.2 so I plugged in the ethernet and installed it which has fixed my WIFI... for now, I'm to scared to restart my Mac. Does Anyone know what is going on? Thank you
Like I said when it gives the error (No WIFI Hardware installed) the wifi connects in recovery just not on my Mac OS. I'm currently using my Mac to submit this question and all seems fine so far.
Thanks again.

Answer 1

Try these in order testing your system after each to see if it's back to normal:
1. a. Resetting your Mac's PRAM and NVRAM
    b. Intel-based Macs: Resetting the System Management Controller (SMC)
2. Restart the computer in Safe Mode, then restart again, normally. If this doesn't help, then:
Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the Utilities menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
3. Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the Utilities menu. Repair the Hard Drive and Permissions as follows.
When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the main menu. Select Restart from the Apple menu.
4. Reinstall Yosemite: Reboot from the Recovery HD. Select Reinstall OS X from the Utilities menu, and click on the Continue button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible
            because it is three times faster than wireless.
5. Reinstall Yosemite from Scratch:
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
How to Clean Install OS X Yosemite
Note: You will need an active Internet connection. I suggest using Ethernet if possible
            because it is three times faster than wireless.