I assume you mean a 2nd hard drive you've added to an existing system.
A blank hard drive usually does not have any partitioning present. Windows probably does recognize the drive, but does not show you any "drives" because what it shows is really the partitions (logical drives). Windows "drive letters" are partitions (a hard drive with 3 partitions might have drive letters C: and D: and E: ). Linux and other flavors of Unix-like system let you have drives AND partitions both be given names in the naming scheme it uses. In Linux, drives have letters and partitions have numbers. BSD does it the other way around, but you can still access either the drive or the partitions.
Once you make a partition AND make it have an appropriate Windows type, then Windows can access it.
Show us how your drives are set up by doing the command "cat /proc/partitions" in a terminal and put that content in a code box here. You should see a few lines with the name in the 4th column. Names without numbers are whole drives. The same name with a number appended is the partition on the named drive.