... arcane linux knowledge collected over the eons, bit by bit ...
When setting up a dual-boot computer or even simply a new Windows computer:
1. Have a Linux Live CD/DVD/USB handy. It’s almost guaranteed that you will need it even if you’re only installing windows.
2. Save the MBR (“Master Boot Record”): Boot your Live linux and in the terminal type:
sudo dd if=/dev/sda […]