built-in screen flickers on macbook air

I have an early MBA 11" (Jan 2011), dual booting to Mavericks and windows 7. Recently it has started exhibiting the following symptoms:

1. 
   

   built-in display flickers during boot and continues to flicker regardless of which OS I boot or display resolution. the flicker is hardly noticeable when displaying a white window full screen but very noticeable on darker colours. If an external display is attacked, that works fine.

   
   


2. 
   

   after closing and re-opening the lid, the display stays black. If an external display is attacked, that works fine.

   
   

I recently installed a video driver update in Windows which I assumed was unrelated because the problem isn't limited to Windows, but a colleague tells me that driver updates could flash the firmware?. I have done a PRAM reset but this didn't make any difference.

I have used the laptop a lot in both Windows and OSX, with and without an external monitor, and never had any problems before.

Any thing else I can try before taking it to a repair shop?

On a related point, should I take it to the apple store or is it safe to use a non-apple repair shop (who claim to be apple experts)?