If the window closes so soon, that suggests something is seriously awry with your Office installation. An uninstall/reinstall may be required. None of your settings or documents should be affected by this, though it's always advisable to make regular data backups - and especially before making major system changes. Before going down that route, though, see:
https://support.microsoft.com/en-us/kb/921541 &
http://word.mvps.org/FAQs/AppErrors/...artingWord.htm