I'm several Word updates behind you (Word for XP), but that happens to me sometimes, I futz with the for mating menu to see if it isn't some flukey thing happening with that (and make sure you're on that second page before doing that), then check the tab thingies. Worse comes to worse, I cut and paste the second page into a new Word doc to see if it does it there, too. If it doesn't, I'll open up a third new doc and copy/paste the first page onto that and see what happens if I add that one row that makes it go to page 2. If nothing wacky happens with that try,then I'll see if I can copy/paste the new doc with just page two right under the new page 1. Sometimes it works. Then I close the original and save as the new doc as whatever name I gave that last doc.
If none of that works - you have to do the annoying - either see if you can find a Microsoft support site apart from Microsoft itself or go to Microsoft support and pay for answers. Sorry, I'd sound more technical, if I didn't learn Word way back when (Windows 3.11) and wing my way up to my present version.