When I accidentally corrupted my 32GB SD card, I tried re-installing one of the older Raspbian ports, and it kept reporting not enough room on the card.. I later found, using Disk Utility under Ultimate Edition UBUNTU, that the card is partitioned off, and Windows only saw the 59MB FAT-32 portion, but couldn't alter the EXT4 partition. (no matter what I did, even under Computer management-removable drives under Windows-7 administrative commands.) result, I had to remove both partitions manually under Disk Utility, then re-formatting it, and re-partitioning it to a single FAT partition.. (I imagine a 4GB flash drive I have, which had a non-writable partition for utilities might be removable the same method.)
Once re-partitioned and formatted, it's 100% usable again under Windozer.. (but.. why?)
Ironic, I accidentally killed a KOBO e-Reader. (Original version, had the navigation pad on the lower-right corner.) When I stripped the device, I found a 2GB Micro-SD inside which had the main OS & stored eBooks. In an EXT2 partition! I was able to finally access it, and recover the purchased books, once I fed it to the desktop with the Disk Utility to mount & read the card.