i think that's part of the risk of lending out dvds and stuff like that in the first place, imo. it's a really crappy situation and i'm sorry it happened, but maybe you could ask if she could at least pitch in and help you buy a new one? or see if you can find the guide online somewhere? i don't think she should have to pay for a new one, because while it sucks and shows she's clearly irresponsible, you took a chance on her in the first place to take care of it.