PC wants to format Scroll

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Bought the 8" Scroll a couple of days ago and everything was working great (apart from the clock), this morning when I switched it on non of the pictures, videos or Kindle books that I'd put on were there anymore, but the apps I've installed are fine. Now when I connect it to the PC and Mount the drive Windows comes up with the format disk window. Should I go ahead and format it and if so is it FAT32, NTFS or exFAT? If I did format it where would I get the Firmware OS from to reinstall it?