So I do know this is an older article but I just wanted to say you are spot on. I have a nightmare of a story regarding: The Apple Store, My New MBP, The Airport Card and 3 Replacement MBP. Now I've had this one for a while now and all of a sudden the Airport Card cannot be found but Bluetooth works just fine? I went forward with those instructions and my Airport Card will no be dislodged ever again.
My MacBook Pro from 2009 was having the same issue of not finding the Airport Card. I had it replaced and still no joy. I ended up buying a new MBP and didn't put much thought into the old one. I recently went back to play with it and see if it was in fact the driver and it was fixed in Mavericks. After the upgrade and reset of PRAM/SCM etc wireless still not working just via ethernet cable.
I decided to buy a micro USB wireless adapter from Amazon for like $25. It just came in the mail today. I downloaded the driver and utility, installed and restarted the laptop.....bam the Airport Card was recognized and is working perfectly!
Could be a coincidence or it could be a possible solution. Just putting it out there. Driver was for a Bolse BO-N1557 Wireless USB Adapter. Worst case scenario I have the Wireless USB Adaptor as a backup.
I had this problem pop up one summer afternoon right when I entered the Studio, it raised its ugly No wireless hardware found. head. To fix it reset the P Ram by holding Control> option> P>R
restart laptop. If that doesnt work. Reset SMC . If that doesnt work see a Genius Bar. It may a real problem. Air card down/cable loose etc.
Thank you so much for sharing your solution!
The post-it trick seems to have worked in my case too! The constantly failing wi-fi was driving me mad! I tried every single "fix" I would find out there, and nothing worked for me. I was a bit desperate and was about to buy a new antenna... But it seems that the issue was actually there, in the connection of the cable to the motherboard, and putting some extra pressure there did its job.
I have been researching this problem for literally five months. Did everything every forum post or suggestion online had. SMC, PRAM, NVRAM, trashing preferences, etc. etc. and nothing. I had been without wireless on my early 2011 13" MBP for almost five months. I even went so far as to replace the wireless card. I would get solutions that worked for a day, maybe even five minutes, but literally nothing stuck. I noticed that if I got something to work and didn't move my laptop I could keep my connection longer, but eventually I always lost the connection. I knew it had to be a hardware thing and the fact this popped up around Mavericks/Yosemite was just a coincidence.
Then I ran across FEEEL's post and tried it out. Post it note, folded up three times, placed it on the ribbon connection to the logic board and the back case and I am soon happy to report that I have my computer back! It's been over fourteen hours and I've moved my mac around quite a bit and I still have signal. If you haven't tried this yet give it a shot.
I have had the same problem with my MacBook Air 2011 + Yosemite... for 3 months now.
Just Today, I connected through the ethernet port and downloaded all the system updates through AppStore. Then, after all the installations (2.65 Gb) and restarts, the system is now showing me the option to add a WiFi network from the network services dropdown.
I called Apple, ran through some things they asked me to do (power off then power on by holding down command, option, p and r and then when that didn't work, powering off then powering on and holding down command and r) which didn't work at all. I restarted my computer 6 times and the wifi still said there was no hardware installed.
What did work for me:
Thankfully (and ironically) the last time I took my MacBook in to get repaired for something, they didn't screw the back lid on back properly because it pops off very easily unless I have a case on. I popped off the lid, and the only thing I saw that seemed loose was the little black square circled in my image. I popped it back into place, restarted my computer, and the wifi worked again. I don't know how to professionally pop off a lid that is properly screwed on; that's the biggest downside to my method, unless you're fearless and aren't afraid of cracking your laptop open.
This is the second time this happens to me, coincidentally both nights before a big exam. The last time I remember doing the same thing (poking around the computer after taking the back lid off) and somehow, it worked too. This time around I have a detailed photo to tell you exactly what I did. Hope this helps!