There isn't anything wrong with her Office or her layout. The Ribbon expands to take advantage of available space, so it looks different on different computers, being affected by monitor size and the resolution settings. I use wide monitors at home and at work, so my Cell Styles gallery looks like hers, and I much prefer it.

The bottom part of that scrollbar is actually a "More" button. (Point to it and the screentip says "More".) Click the More button to expand the gallery and see all the choices. Many galleries in MS Office feature a More button if they have enough room across the window to display.