To delete or format an NTFS partition, users can access "Disk Management" by right-clicking "My Computer" and selecting "Manage," then choosing the desired partition. However, formatting the C: drive, which contains the operating system, is not possible while the system is running. To format the C: drive, a third-party tool or the Windows XP CD is required. Booting from the XP CD and entering recovery mode allows users to delete all partitions. Magic Partition software is also suggested as a user-friendly option for formatting partitions.