(it turns out it won't be necessary to actually partition anything out because chkdsk does that in the mft. i did know how mfts work, but i wasn't clear on whether the information coming at me related to the physical sectors or the mft; it's the latter. which makes things easier. a chkdsk is enough; the file system will take it from there. and, thankfully, it does seem, right now, that the corruption is just at the front of the mft.)

i should point out that i've got the disc split into a small operating system partition and a large file partition. it seems like that's going to save my data, even as the os needs a fresh install. which is why i did it like that.