First, i think you're confused between memory and harddrive. Your hardrive (C:) is used for storage not memory. Memory is the amount of RAM you have.
Secondly, are you sure that both drives are 228GB, usually the second drive is a 'recovery drive' which can be used to restore the machine to the factory settings and is of smaller capacity. I am assuming this because you've called it DATA.
Thirdly, to free up any space on the C: drive, you could always back-up some files etc