Walk the perimeter and try each basement window. Does the latch engage fully? Does the sash close without being pushed? Is the frame sound, or does it flex and crumble at the edges? Are the hinges or slides intact?
Old crank windows and hopper vents often have simple catches that do not lock at all, or that have been painted solid in the open position. Glass block panels have no opening at all, which is why some households replace windows with them, though that removes any use of the window for light or ventilation.
Write down what you find. A window that cannot be secured is worth dealing with before anything else is added.