Go to your primary output (In my case its "Speakers").
Right click on the speaker in the bottom right of your tray. If I take a screenshot or Fraps record for a second, everything still comes out at 2560x1440, so I'm inclined to. Flawless widescreen and Widescreenfixer both either don't work or do very shoddy jobs at making the game run at 3440x1440.
Trying to make Skyrim run at 3440x1440 (aka 21:9 ratio resolutions.) I'm just about ready to give up. Either the Khajiit, Redguard, or Wood Elf races make excellent Rangers due to their Archery bonuses (20, 20, and 25 respectively). Advice: To be a Ranger in Skyrim means that you need to be good with a bow, proficient in sneaking, skilled in arms, and have good healing abilities.