Why isnt my wifi working?

Hi I recently put in a new wifi antenna as I was having issues with my old one. I have made sure the long screw at the top is in. However one of the other screws at the bottom second left side cannot go in as the tiny metal thing which the screw goes into is no longer on the board beneath it. Does this make any difference as to the wifi working or not? As I thought the most important screw was the long one at the top.

EDIT: The wifi is not completly not working, its up and down most of the times. If I am in the same room as the router then it is fine.