This doesn't exactly fall under the SCL so I made a new thread. I tried the two installers from the Communications sub area of H/PC:Update for the NEC MobilePro 780. After installing both (128-bit first, then schannel.dll update) I could no longer use security functions. I re-installed the 128-bit update and things went back to normal. Since the schannel.dll update only writes that one file (and seems broken), I would suggest a note stating that only the 128-bit should be used (or just delete the schannel one).
The schannel update is an official NEC patch and is probably 64-bit. The 128 is a MS update, In your case you patched it to 128 and then downgraded it without downgrading the registry, so it broke.
I see. Maybe just a note stating that they're not intercompatible then? In my ignorance I thought it would be a good idea to simply apply all available updates