I want to create E: drive in addition to C:
Start -> Control Panel -> Administrative Tools -> Computer Management -> Storage, Disk Management -> Right click in free space (if there is no unreserved space, shrink a partition by right clicking on it and choose shrink) and choose "Create new simple Volume". This will create a storage partition similar to C:.
What exactly do you want this "E" drive to do, to be or to represent?
Do you want it to link to the same storage (Hard Drive) as C, do you want it to link to a specific folder, do you want separate storage (partition), do you want a Virtual Drive for mounting disk images?