I know this is little old topic. By the way, I want to explain this problem. I'm also have this problem and go after any methods. I feel better when I know there are other people have same problem with me. (Because it make me to know that's not rare problem - I'm not mean just temporary template corrupted) Sorry for my bad english.
But I think this will help people that have this problem like me. (At first time I just think it's because I'm not found where is it lol)
First I search about template and find how I can add/fix it. Finally I found 2 source of template. (You will have it in your computer.)
1. Building Blocks.dotx 338kb
2. Normal.dotm 16kb
#2 is normal word template. So that's corrupted file. When you use it, it'll not contain page number template. The way you can do is just insert same number on any page. e.g. every page with 1. That's not what we need.
Then I open #1 (Building Blocks.dotx) It've template. But it can't edit view (Default with web view) that I will tell why later. This is annoying. You must open with it and change its view every time you want to create new document. (Or use your old or your friend normal document one to clear all for reuse)
The next things I do by my default not have to search via internet is test to delete Normal.dotm Yeah it's re-create 'With old empty template'. (By the way you should try this. It'll help with normal problem.)
So I re-install my MSOffice. (More than one time - -') <- To tell you that won't help. It just spend your time.
I try to use Building Blocks.dotx to help about this problem for me. First, I save it to template dotx It'll create 15 or 16 kb 'contain no template'. I try save it to template dotm It also create 15 or 16 kb 'contain no template' again.
I think that cover all what I found and test.
I found later it's not just page number. It's also not have watermark template etc. By the way that can create new one with text watermark option.
#The solution I think I'll tell you is to find Normal.dotm (e.g. From your friend) to replace old file and you should keep its replica too.
Oh, forget to tell you. Same install with another of my PC is work.
(But I'm not sure. I'm not live at my home in this period.)
That make confusion.