How do can I close all windows on Preview and OpenOffice, so they don't open again when I open Preview to see something else?
Firstly, to prevent it happening again, remember to close a document before you Quit, otherwise it will reopen on launch.

To clear the existing list, With both apps quit, go to
~/Library/Saved Application State/  

&amp; delete the two saved state folders, com.apple.Preview.savedState &amp; the same for OpenOffice [I don't have the app so not certain of the name.]

Done.



Quick way to get there, if you're not sure…


From Finder, hit  Cmd ⌘   N  for New Window
Hit  Cmd ⌘   Shift ⇧   G  for Go…
Paste ~/Library/Saved Application State/ including the tilde ~