I added an entry to sceregvl.inf, and realized it was supposed to be
boolean instead of string. I had already registered it, and so went
back, changed it, and reregistered with the correct setting. Now
"security options" is empty in the mmc.

I tried copying a backup untampered version of sceregvl.inf, and
registering it. That failed to fix the problem. So, I tried to
rebuild secedit.sdb by moving and renaming it along with the log
files. I used security config and analysis, however, even in safe
mode I'm unable to create the database in %systemroot%\Security
\database. I get "import failed, access denied". So I tried letting
gpupdate /force create a secedit.sdb. But I'm unable to open that
database as I get "access to database has been denied"

Any ideas?