I was trying to fix my Dad’s PS3 (he recently passed away) nothing was working, so I connected the HDD from the PS3 into my PC. Upon plugging in the SATA cable, the entire PC shut off. I unplugged the HDD, but now when I power on the PC, the fans just run at max speed and nothing else happens. I don’t know how to troubleshoot this problem.
If your board has the option to turn it on or off then hotplugging with it off won’t break anything. It just won’t poll for new devices.