Q: IMac 21.5 inch mid 2011 frezze issue fix work for me

After try so many fixes, contact apple engeniers, genius bar with any solution because some people try to cover the issue because is bad publicity

I think I find the solution

1 I download fresh copy of lion from apple app store and I put it in a 16 gb USB do the Bootable usb with application is in apple webpage

2 I format the hard drive all the partitions include hd recovery I use terminal for do that

3 after all the partition is erased I start to install lion from the USB fresh Install when you that again is created the hd recovery and Mac os x lion partition like when you  buy the iMac.

After so  many test not come back the problem again I have 5 months not issues and I do for my self apple don't find any solution bla bla bla

Just for the people have flickering screen is because the iMac when start enter to safe mode for him self because is not detected Bluetooth keyboard and mouse when you start your iMac don't put it on the keyboard and mouse until loggin screen appear.

I hope help some body and if you try my solution and help you send me a message.