How to dismiss a window without a close button

The installation of Offisync left a window displayed on the screen without a close or minimize button. It's annoying since that window blocks almost 30% of the viewable area of the screen. The Applicatons tab in task manager doesn't show any trace about it. I had to resort to Process Explorer, which has a nice function called "Find Handle or DLL..." with a hotkey (CTRL+F). After I pushed CTRL+F key, I entered "Offisync" as the handle or DLL substring to search and the result returned has a process of Rundll.exe, which I killed to dismiss the window.