Follow-up: I went into the ME side of my computer and found mrbupd.dll in a couple of places. I copied it to a folder that my platforms have in common, and restarted the computer. I've copied the file to the place where it is supposed to live. I'll test if it "takes" later when I reboot the computer.

I suppose this should serve as a cautionary tale: don't let programs you're uninstalling delete common files. It may be a little extra baggage, but those uninstall programs aren't necessarily the best way to take care of disk cleanup.

SRS