screens not visable

When I go into the Operations Tree and attempt to replace a tool in the tool crip, the screen for selecting the new tool is off the screen and not visible.  Have tried the Alt-spacebar-M method of see hidden screens....... cascade windows......  kind of puzzled!!  I do have 3 external monitors on my work station.  The menu is not on any of them!!  Can anyone help??

SolidworksGeneral