Not sure which thread this was hiding in, but it solved that problem, while creating others. With Windows running "normally," I inserted the CD and chose Install Now, then Update. It went through a few steps, went to reboot itself, then did BSOD.
So I removed my trickery: uninstalled Rollback and genericized the MBR to remove Grub. Then I tried again. After reactivating, it worked and fixed the Features problem, but the two hundred accompanying updates are still taking forever.
The upgrade doesn't seem to have done much other than fixing said problem and forcing me to install endless updates, reenact my trickery, reinstall and rescan AVG and more to come, I'm sure.
...not sure I needed it that bad.