First of all, you need a program that can save a png file, like Paint.NET. You need to change the opacity of the layer you want transparent from 0-255. 255 is a completely opaque layer, 0 is completely invisible.
If you are on Paint.NET, find the layers window. Click the icon with a tag and a pencil, that should be properties.
You should see this window. Drag the "Opacity" slider to a transparency of your choosing.
I have an art request (sorry if this bothers you). You don't have to do it right now, do it whenever you want. It's Nova staring at the screen with open, black eyes. The eyes are slightly glowing and they have black goop oozing out of it a little.
Eyup, I want it so say "NF Deathmatch" in the same style and font as the one you made for the Choice Awards. And also if you could add zest, I dunno, maybe a silhouette in the same color as the logo symbolizing war or something? Png transparent btw.