I've run the update troubleshooter; I've run the update assistant; I shut down a bunch of boot-loading utilities; and I've run the memory diagnostics with clean results.
Every time, I get a BSD during the update that says "MEMORY MANAGEMENT".
At this point, I'm getting notices from Windows Update that security updates require this version, and it downloads and pesters me on a regular basis. I'd appreciate any advice on what my next diagnostic steps might be to get around this block.