This will happen if you Close Poser Minimized.

You can edit the Poser UI to fix this, if you do not want to lose custom settings. Before Launching Poser, Open the UI Preference File and go to the end and look for Open Maximized and change from 0 to 1... or you can delete the UI Preference file

For those using older OS, just right click and select Maximize...  (Right Clicking in Windows 7 on the item in the Task Bar, and right clicking on the Program name in the right click menu then selecting Properties will allow you to change the Open Options. This works for some users... does for me on Windows 7 32, does not on Windows 7 64)

ratscloset
aka John