1. Disconnect the machine from the Internet so that you can start Process Explorer without waiting a while.
2. Start Process Explorer (elevated), View lower pane.
3. Connect to the Internet and wait.
4. When the system starts going crazy check for a second instance of explorer.exe (will probably be there even before connecting to the Internet, but won't be doing much), and view the lower pane to look for that hidden folder/file in C:\ProgramData named {9A88E103-A20A-4EA5-8636-C73B709A5BF8}.
5. You can now kill the process but it won't help much since it will regenerate. You can't rename/remove the hidden folder since it's in use.
6. Boot to Recovery Environment, command line, unhide the hidden folder and rename (I added "bad" to the name in case I have to revert the change).
7. Boot to normal mode, check Process Explorer to see if the rogue explorer.exe appears. Check the formerly hidden folder. Previously it had 3 files in there, but now there should be only two. Unclear why.
8. Run D7's cleanup routine to clear "everything" out. (I also manually stopped and started System Restore to delete all restore points.)
9. Reboot and check Process Explorer to see if the CPU, RAM "and" HDD activity is normal. Check IE history to see if it's still populated with all those ad sites etc. Let it wait for a while connected to the Internet to ensure nothing funny is happening. (At this point when I checked the hidden folder again, there was only one file (a .dll) in there. I now moved the folder to the Support subfolder on the C: drive. still unsure if to delete it since I couldn't find anything in regedit or on the internet regarding those file and folder names.)
10. Run your typical post-removal routine, update everything, educate client, get paid.
The End