If you have a machine in a multiboot environment with the new Windows 8, you need to turn of the Fast Start option in Win 8.
It is possible that this feature in Win 8 corrupt your other windows partitions.
It happend to me when i want to check out the new windows version in a separate partition on my laptop.
Win 8 totally f.... up my partitions (excuse my english).
After googling around it seems a known problem......
So be warned when you want to check out the new 'vista' under the windows versions ;-)