Connecting Macbook Air to HPw1907 external screen I have recently brought a HPw1907 external screen for my mac but having trouble connecting it. I have connected a VGA cable but as soon as I turn it on, the monitor goes straight to sleep. When I open the display setting, I don't have the 'gather windows' or 'arrangement' setting unless I choose 'apple tv' in the drop down menu but that detects our Apple TV rather than the screen.

Any tips?
Since the the MacBook Air does not have VGA plug I would say

... your Thunderbolt to VGA converter is not the proper one.

That would be also the reason why it does not correctly detect the HP monitor. 

Try the Thunderbolt to DVI adapter instead.