The power switch is ALWAYS at the back of the computer
I remember there were TV programs aimed at newbie PC users.
This was in the days that I was repairing (to component level) Commode PETs (because I once did an Intel 8080 assembler SDK course).
The TV explained that the power switches were on the back so that the computer could not be powered off accidentally.
Late 1980's IIRC.
Les in Manila (retired)