I'm not sure how to best phrase the problem so please bare with me.
This problem has happened to two different coworker of mine while they were in a specific drawing. The drawings that they were in were completely unrelated and the problem only occurs within that specific file.
It seems to happen when they switch to paperspace and zoom in or out or do anything related to the viewport...the original view of the tab remains and at the same time, they can see the zoomed in image. If they could ignore the double image they can continue to work in the file as if nothing is wrong. If they switch to another tab or model space the original paperspace image from the 1st tab follows to each screen.
The duplicate image cannot be selected, there is only one viewport per tab and they are not stuck in it.
Once the file is closed and reopened, the ghost image is gone, until they zoom or click on a viewport within paperspace and then it starts all over again until they save and close.
FYI, within the viewport in an xref'd dwg with hatches and dimensions laid on top, both coworkers have newer computers, one was on CAD 2007 and the other on CAD 2009, and I have opened the files with 2009 & 2010 and have not been able to duplicate the problem.
Sounds like those new computers have graphics cards that arn't fully compatable with your version of AutoCAD. Check the list of certified hardware (http://usa.autodesk.com/adsk/servlet/hc?siteID=123112&id=6711853&linkID=9240618). As an experiment, you might try swapping the card from one of the machines that is not having the problem into one of the new machines to see if the problem goes away.
I've just run into this problem too. Opening an old drawing (actually recover an old R14 dwg into ACAD 2008). Once dwg was recovered, if I pan or zoom (in model space) the original image doesn't move, but a duplicate does. I cannot select anthing on the "ghost" image, but when I select an entity on the "other" image, both images highlight (grips, for example appear on both). If I draw an entity in a area of the "real" image, an exact copy is drawn in the same area of the "ghost" image. For example, suppose I have a box. When I zoom out, the "real" image of the box gets smaller, but the "ghost" image remains the same. If I pan, I can pan the "real" image completely away from the "ghost" image. If I draw an entity inside the "real" image, that entity shows in the "ghost" image - but, just like the "ghost" image, it is not selectable. If I save the drawing with the two images side-by-side and reopen it, the drawing shows both images just as they were last saved - side-by-side. Even the drawing preview shows two images. Audit finds no errors. I've opened the drawing on other computers with different hardware and different version of ACAD and see the same thing. Has anyone figured this out yet?
This might not be helpful at all but, for the user who has both 2009 and 2007 users -- is the drawing being saved backwards in 2009? And are there any annotation objects created in that file in 2009? I only say this because in 2008 or newer, the SAVEFIDELITY variable controls whether annotation objects are translated into multiple objects on individual layers for users of 2007 and older...
I hope my info was useful, but if by some odd chance it actually solved your issue, feel free to mark your post as "Accept as Solution". Thanks!