The 64MB size and description of your sister-in-law leads me to suspect she removed it from her pc without using the Windows USB Safe Removal option and the FAT got screwed up. A fairly common situation.
The unable to format under a pc or a MAC is a tougher situation.
What kind of error msg does the pc give when you try to format it?
Are you running Windows 7? Are you using a Limited access user id or an Admin one?
Try booting the pc in Safe mode and then try formatting it. Try erasing LIGHTLY the contacts on the Blade. Try cleaning the USB contacts on the pc.
