Yeah it's the general slowness of windows and stuff with laptops like that over time. But I'm sure she's dropped it before since the screen is wonky and wireless goes on and off. I like the thinkpads even though they are ugly. I'll need to check those out too.
if you're interested in them check this guide
http://www.ktgee.net/post/49423737148/thinkpad-guide
I'm waiting for a x200 to arrive, might be too slow for you gf, try the newer models though. She'll love the battery life and portability.