Can you set control panels to float and drag them to the other screen?  Have you set Windows to extend your desktop to add the other monitor?  If Windows does not offer the option of using the second monitor at its full resolution, this likely due to your video card -or worse, "onboard graphics"- lacking enough capacity to drive both monitors at full resolution.  You may also find that if you have two moderate cards in SLI (or CrossFire), you may have to remove the SLI/CrossFire bridge and run one monitor from each card.

     While using whatever extra monitor you have on hand is better than having one monitor, if you plan to use dual monitors, I strongly recommend getting two which have the same pixel height (different horizontal pixel count is unimportant).  Examples:

• two 1920x1200 monitors
• one 1920x1200 and one 1600x1200 monitor
• one 2560x1600 and one 1200x1600 monitor (this being a 1600x1200 monitor, rotated 90 degrees to portrait orientation rather than the default landscape orientation)

     With both monitors having the same vertical pixel dimension, you avoid having any "dead" areas on your desktop where shortcut icons and control panels can get lost.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5