The Hidden attribute prevents accidentally deleting a file. GDI is the acronym for graphics device interface. They are managed in the Control Panel under the Enhanced choice. WIN.COM starts Windows. WIN.INI is not necessary, but it is created if it doesn't exist.
Safe mode loads VGA drivers and keyboard drivers, but no network drivers.
F8 interrupts the startup, providing for a text startup menu of choices. WINS means Windows Internet Naming Services. Ohms on a multimeter. ESD is electrostatic discharge. EMI is electromagnetic interference.