mac air weird problem after keyboard replacement

[bradlfc]

I changed my keyboard on my Mac air and as far as I know I changed it successfully I was very careful and followed a step by step tutorial, but.....
When I press some of the keys higher on the keyboard eg 5,6, F5,f6 in particular the laptop will just turn of for know reason? The only thing I didn't replace wast the black plastic under the keyboard because the old one was damedged. I was thinking that maybe it was pressing on the logic board , but would this cause a shut down ?The rest of the keyboard works fine not a problem.
But it was not replaced with the original keyboard it was replaced with a keyboard fron the next model ( with backlight)
But can't see this being a problem as it works fine apart from the upper keys?

If anyone can share some knowledge it would be highly appreciated.

Excuse the bad writing and grammer!