Did she delete  the view  or the content? If content, then the entire web part needs to be restored, at a minimum. If the view, then she should be able to re-create  the view.

I was able to restore  the threaded  view (AllItems.aspx) back but using FrontPage.

This is what I did, I changed the default view  to Flat view on a discussion  board. Then I was able to deleted the threaded view ( like the user  in your company deleted).

Then I created a new discussion board  and using FrontPage I copied the AllItems.aspx page and pasted within the old one. Then I had to change the List GUID on the AllItems.aspx page. When you click "Modify settings and columns" you will get the list ID number on the address bar, example

List={8A15BA2D-6F15-4202-BF9A-4A8AADB1A0DB}

Put the ID of the old discussion board in AllItems.aspx file and you will have the Threaded view back, later you can make this view as the default one.

But this is using FrontPage.

Also please refer to this article for help.

office.microsoft.com/.../ha010990371033.aspx