use tweakui and remove g drive from being shown on my computer... while this is not really solving the problem, it is a workaround that should be enough...
i had the same trouble some months back.... i deleted/modified/created some new partitions using the disk management tool and suddenly a new partition showed up which was never accissible... did you also recently modify partitions?
i did what sakumar above has said and simply hid the drive using tweakui.....
reinstalling windows didnt help so i later 'fdisk'ed my hdd... now its ok....