Had a few cases of "talented" people breaking stuff, mostly of the "OMG you blew up my broken power supply with your flaky MB, get me a new one right now!" then "Actually thanks, the replacement solved my PC problems which have been going on for months, k"
Recently had a spate of motherboard and HDD failures which I traced back to glitchy power.
Somehow despite the units being behind 2 (!) layers of surge protectors the mere act of turning off power was enough to eventually corrupt the CMOS and trigger a failure.
There is an argument that MB CMOS batteries are prone to failure and even just knocking the PC can be enough to break them.
I had a machine which somehow lost its CMOS settings when doing a routine test, despite the battery being at 0.01V it somehow managed to hold its memory because the board did not work after that.
Pretty sure that they have sneaky software that detects a date/time change in any files past 2006 because thats about the only thing which changed when battery was replaced.
The act of metering it was evidently enough to wipe everything so its going to be very hard to fix.
Also had SSDs kill the attached machine, seems that people end up replacing hardware because they swapped HDD for SSD then laptop boots fine once or twice and never again when cold started.
Pretty sure this qualifies as "strangest fail ever" as the SSD tests fine in a USB and works in my laptop
perfectly well but going to send it back anyway because its firmware won't update at all.
I am going to check the screen memory because this is a well known problem with 10 on some chipsets and it wipes out a crucial byte in that 8 pin memory used to ID the panel.