Re: Mounting drives - issues
You keep saying "drive" but I suspect that these are actually partitions -- all on a single, physical drive, right?
Since you can access that partition in Win7, next time you boot into it, open the Disk Management utility and look at the partition. If it says Dynamic Disk next to it in the table at the top -- Linux can't use those types of partitions, but Win7 can.
Ubuntu 16.04 Mate, Mint 18 Mate; MS Win 8.1, MS Win10 Pro.
Will not respond to PM requests for support -- use the forums.