I wanted to add an additional computer monitor for my studio........I know how to do it providing you are looking at the same screen on both monitors.....but if I wanted one to display Sonar's (I have the very latest version) track display and the other to show mixer display....is that possible?
Thanks

Yep, simply drag the mixer into the second monitor. You may have to right click on the desktop and adjust your video preferences (I can't remember). But that's the way I'm running X3 now.

Awesome...thanks!

You have to right click on the screen and pull up display control, Windows or a proprietary one for your graphics card. Under Multiple Monitors, have it search for monitors if both aren't already listed. When you have both listed, you have to decide which is Primary, with your icons etc, and which is secondary.
 
Next up, choose whether the additional monitor extends or clones the primary display. You want to choose 'Extend' to make more room for different Sonar screens.
 
Then you have to tell the computer how you have them arranged physically, stacked vertically, side by side in 1, 2 order,  side by side in 2, 1 order, whatever. Get this wrong and your cursor has to travel off the right side of the right screen to enter the left screen, if side by side. If you have a problem with primary/secondary and arrangement, keep plugging, it CAN be done, YOUR way.
 
Then drag your screens where you want them and save the Project, or set up your screensets and save.