How to bring a lost window back to desktop ?

You may come across a issue: you can see an application open in taskbar , but you cant find in the desktop. Some of the reasons such as disconnecting ur pc from secondary display, program that alters resolution, and few other ways the problem occurs.

Get it back on Windows 7

Focus on the troubled window by clicking on Alt+Tab key.Now hold the windows key and press up arrow key.With any luck, the missing window will magically come to desktop.

For windows vista and earlier version 

Right-click on taskbar of the program and choose ‘Move’. Now use arrow keys to move the window. You can also use right click on the taskbar and choose cascade windows to show up the missing window.