Ramdomly while using AutoCAD MEP 2012 my crosshairs disappear, only the crosshairs, the mouse (windows "arrow") still works and response and let's me select autodcad menu items, or type in the command line, but once I get into the graphics window the arrow doesn't change into the crosshairs, it just disappears completely. Moving the mouse around you can see the standard arrow head cursor reappear and disappear as your cross the drawing window "border". But the crosshairs never reappear. Sometimes this happens when switching from Autocad to another active window. (outside Autocad mouse cursor still appears) and at other times when switching from one drawing to another. The crosshairs will show correctly in one drawing but not the other. The corsshairs will not "reappear" until I close out the drawing they are gone from and reopening it.

Is there a command to use inside autocad to "reinitialize" the mouse?

Windows 7 - 64bit,
i7 processor, 12gb ram, ATI 4800HD graphics card w/512 mb ram.
microsoft Laser mouse 6000.
All drivers current and uptodate on both graphics card and mouse.

This seemed to have started after the last AutoCAD service pack / update.

Any ideas?