As you've found, formatting an MP3 player is not always advisable.
Please supply the model number because Craig has a range of products.
Meantime if it's a simple stick model (like a memory stick) the chances are it's a SigmaTel design and those will tolerate formatting as Fat32 (so if your daughter selected NTFS you need to reformat it).
When finished disconnect (and insert a fresh battery) and the device may boot up and apply the necessary software and folders from firmware.
Failing that, with the stick models it may help to remove the battery and press the Menu or Play button as you connect to the PC. This should then activate Windows' Found New Hardware sequence.
My Daughter re formated her Craig MP3 player, and now it does nothing, It accepts the charge from the port, can access it thru My computer, but the drivers are missing.. according to the info I can find Craig has closed its doors. Any chance someone out there might have a download to re install the drivers or something?