Exit DxDesigner, and delete (make a copy of DxDesigner.wsp) found in your local wdir directory. This will create a new DxDesigenr.wsp and reset the window positions to the default locations.
The general solution for an off-screen window (Windows XP):
(a) Do whatever is necessary for the window to have focus e.g. select it on the task bar (if visible there) or invoke the command to open the window.
(b) Press Atl-Spacebar
(c) Press M (for move)
(d) Press one of the keyboard arrow keys
(e) Now move the mouse - the window is attached to the mouse cursor
If you try the above process on a window already on-screen you can see what is going on.
Set your flow to PADS > Design Entry > DxDesigner
I searched for "reset window location".
Result 2 was TechNote MG26162, dated 7/24/09 which explains how to reset the window position for various versions of DxDesigner. The version you are using is a later update of DxDesigner 2007 so follow those instructions, which is to delete DxDesigner.wsp
We would appreciate it if you avoided cross posting, but I will ask that the Technote be enhanced with the new version numbers of DxDesign.