Fdisk allows you to manage partitions. You can delete or create them. If you do not touch an existing partition it is safe, although strange things can happen if you delete C and leave the other(s) intact. Please restate again how the system is now and how you want it to end up and what OS you are going to use on it.
Once the partitions are set, all the resulting drives - primary and logical - will have to be formatted to be usable.
Hint: If you delete a partition to try to rearrange things that data is gone forever for all practical purposes.