Carlos,
I am having a similar problem. I am running on Windows XP Pro, Core duo processor, and I am running the latest version (1.00.58.377).
I opened up a JPG, and the system locks whenever I move a window. I can execute commands, undo/redo, but whenever I move a window -- image or control -- the system locks. I can unlock it with alt-ctrl-delete, which brings up the task manager and frees up the system.
It is interesting to note that the moved window freezes after moving about 40 pixels, but the final window position depends on where you finally release the mouse button.
--Andy