It should be possible to sort out your problem by 'digging under the hood' a bit with OpenOffice. Alternatively though, uninstall OpenOffice, RESTART YOUR COMPUTER (IMPORTANT!), run CCleaner to flush out any remaining entries, RESTART YOUR COMPUTER AGAIN and then reinstall OpenOffice. (That's the only way to ensure that you get a COMPLETELY fresh installation. I recently had to do the same thing to cure a recurring problem with VLC).
However if you still want to try a different freebie, there are two highly-recommended alternatives. The first, LibreOffice, has already been suggested. The other is WPS Office. (It used to be called Kingsoft Office Free and gained fantastic reviews from many sources. The name might have changed but the software seems to be as good as ever):
http://www.ksosoft.com/product/office-free.html