So, long story but basically shortly after i upgraded to Lion I started experiencing problems with Wifi. Wifi symbol was greyed out and when hovered over icon a message appeared saying 'no hardware installed'. I did some research online and I found it was an issue many had experienced after upgrading to Lion. After numerous visit to the Apple store and a call to Apple Care, who admitted it was a problem they were aware of but mainly affected only iMacs (and an update had been released to fix this) I had a replacement Airport card, then when the problem persisted a new display (as this has Wifi antenna built in) although my issue was not being able to turn wifi on, not being unable to connect to a network. The issue now is that after 6 or 7 months the problem has returned. Has anyone else experienced anything similar or know what else could be the cause? I don't have trouble with any other devices connecting to my Wifi. Due to a bad customer experience in store I had previous 'repairs' free of charge but as the problem has returned so soon, I would be reluctant to pay £350-£400 for a second hardware replacement and I am also now out of the 90 day extended warranty.