Setting the default page size isn't exactly rocket science.

* On an empty document, set whichever settings you want to become defaults. (So change the page format, modify the default text style, any of that stuff.)

* Now select "File / Templates / Save..." to save it as a template.

* Next, go to "File / Templates / Organise...", select your template (double-click "My Templates"), and click "Commands / Set as Default Template".

Next time you start up OOo on a blank document, it will use your changed settings. Not just the page size, but everything else you set.

Funny how the MS apologists and open-source knockers always post anonymously. Must be to hide their MS piecework payments from the HMRC...

Paris, because even she knows how to use the help system. Duh.