Problem seeing render in compositor and transparency

Support Compositing and Post Processing
1

When I go to compositor by image does not come in background. I tun on backdrop and I render but it is blank. If I switch from RGBA to RGB it goes black. I’m not sure whats wrong.

Screen Shot 2016-07-22 at 12.53.04.png1014×549 47.9 KB

Screen Shot 2016-07-22 at 12.53.08.png903×559 41.1 KB

Also problem when I render, the transparency disappears. I have freestlye on but it still not transparent when i turn off. In middle of render there is transparent but when finished it goes black I dont know why. I have transparency in film turned on and output set to RGBA

Screen Shot 2016-07-22 at 12.53.12.png1391×593 71.2 KB

other pictures http://imgur.com/a/Y5F4S

2

Here is blendWheel.blend (715 KB)

3

The backdrop only shows what a Viewer node is connected to.
And the render turns black, because you have “Use Alpha” disabled in the Composite node:

https://dl.dropboxusercontent.com/u/27650383/22-07-2016%2014-33-44.png

4

Ooohh thank you. Sorry for stupid question. If you have reddit I can give you gold or some other thank you.