NoClose is a free tool that will disable the Close (X) button at the right corner of open windows.

You need this to prevent an accidental click to the close button when you need a window/program to remain open.

Features

Press Ctrl+1 to Enable or Disable the Close button of the active window. – Press Ctrl+2 to Add a rule. – Automatic enabling and disabling of close buttons on program start and stop, and on window creation. – Change hotkeys and automation options.