A user discovered an issue with their HDD where 2GB of space could not be written to, despite the binary point showing it was empty. The discussion highlights that hard drive capacities are measured in base 10 (10^9 bytes) rather than base 2 (2^30 bytes), which can lead to confusion. Potential causes for the issue include bad sectors or complications from low-level formatting. There are references to the possibility of unreachable sectors due to BIOS, OS, or software limitations, and the mention of older hard drives having manufacturer partitions that remap bad sectors. The conversation also touches on the peculiarities of Windows Vista, suggesting it may store data outside the typical file system structure, leading to access errors when trying to reach certain directories. The user expresses frustration with Vista, planning to revert to Windows XP, and notes that accessing certain files can result in error messages, indicating that Vista may have unique handling of file paths and permissions.