“...Apache OpenOffice and LibreOffice...”
Can any of them open Win-7 Office 2007 *.doc or *.docx files?
LibreOffice can open Office files. You can also re-save them in the same format. There might be slight incompatibility issues upon saving.
It is free to try.
https://www.libreoffice.org
Yes to both, but docx files saved with LibreOffice may contain formatting errors when opened in Microsoft Word https://wiki.documentfoundation.org/images/1/13/1_-_File_Formats.odt