That Z68 motherboard is from circa 2011-2012?
The motherboard CR2032 battery is probably dead after 5 years. Easily replaced for about $0.50.
The thermal paste on CPU might be cooked off, it's not really meant to last many years. A tube of Arctic Silver 5 costs about $10.
The PSU could be failing after 5 years, de-rated caps and stuff. It can be tested at any shop. I would cost less to replace the PSU than to replace the whole machine.
The motherboard and CPU and GPU card and DDR3 (and probably also PSU) had 3-year warranty. Worth keeping in mind even though they could still work fine.
These threads about M4EZ Q-Code 92 might help ...
https://rog.asus.com/forum/showthread.php?24113-Maximus-IV-Extreme-Z-wont-boot-error-code-92https://vip.asus.com/forum/view.aspx?board_id=1&model=P8P67+DELUXE&id=20150610084037169&page=1&SLang...
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