This has happened to me twice now.

 After running a conversion in WW for Poser Pro 2012, the conversion finishes but the Poser screen will not restore/maximize.  The program is active but you can't get back into the screen.

So, when you reboot you get the splash screen with the serial number and as soon as that goes away -  I hear a click and then nothing.  Program active but I can't restore or show the screen.

 The only way I fixed this last time was to reinstall.  Anyone see this before or have a suggestion?  I did remove the pref files already and tried that but it didn't work. 

Windows 10 - Poser Pro 2012 - 64Bit - 24GB RAM - 4 x 3.40 GHZ processor