First time I pirated Windows XP.
Bought the disc for 5£ from an ambulant seller who'd sell also porn DVDs (but that's a story for another time)
The disc was in a soft plastic envelope, inside printed in B/W the XP logo and also loose inside the envelope the "serial" to insert when prompted and the instructions on how to install.
I did all the procedure according to the instruction provided and inserted the serial without much hope and sure enough it worked!
Visited the guy for a couple of years for pirated PC games, movies and porn DVDs....good times.