Need a computer book for my mom. Any recommendations?

My mother keeps asking me to show her how to do stuff on her computer. She doesn't even know basic things like folders, internet searching, bookmarks, the list goes on and on. Every time I try and teach her it just doesn't stick no matter how many times I explain it. She forgets almost instantly. IT'S SO FRUSTRATING!! It's like she cannot learn or simply does not want to. Is there a book, tutorial series, blog, anything out there that's any good at teaching older people computer basics? Her computer runs windows 7, so I prefer that whatever tool/book I get her will be relatively up to date. It would also be nice for her to have a sort of reference manual that she can look to when she inevitably forgets.