i have an enb installed for fallout new vegas since you cant have steam overlay enabled you cant take screen shots of the enb so how can i get pics of my enb for my back ground?

Simple, use your Print Screen button on your keyboard. It must be close to your Pause Break button.

Remember, Print Screen will Print your Screen, then go into paint or any program like it, and right click and paste, or use the shortcut to Paste.

If this doesn't do, and print's something else, http://www.nexusmods.com/newvegas/mods/41381/?.
With this mod there will be a Fake Fullscreen, it's windowed mode but it will fit into your screen. Then you hit Print Screen and it will 100% take a screenshot of your screen, then you just paste it into paint. (Don't forget to reply and rate if it did work, bra!)