Odd computer problem - sleeps even before BIOS

[GamingTao]

I am fixing my sister's computer and am pretty stumped this time. The
computer will enter sleep mode at random moments. I thought it was the
monitor but double and triple checked that since it seemed like the
only possible problem.

I want to say it is a hardware failure of some sort, but since I have
been working with computers I have never seen one act like this. It
will go into sleep mode at random times. Sometimes hours before it
enters sleep... however it even went to sleep just before I entered
BIOS since I thought it possibly could have been a BIOS setting causing
the problems (BTW when I finally got in there nothing seemed out of the
ordinary).

So anyone else seen a computer enter sleep mode (the light on the
actual PC even changes colors to reflect sleep mode) sometimes before
even BIOS loads and are unable to get out of it? If so mind letting me
know what the problem was on the computer in question?

BTW this computer is a HP model (getting the computer again today so I
can update if you really need to know the specs) but everything is
exactly as it was when she purchased it, the case has never been opened
only change in hardware is the addition of a printer.

 

[Mark L. Ferguson]

You would need to upgrade the BIOS.


..

 

[GamingTao]

BIOS is up to date and I am still experienceing these problems.

However I will say it isn't going to sleep, It just looks like it. Her
monitor would enter sleep mode when the computer shut itself down. The
LED in front switched to the color for sleep mode so her monitor threw
me off.

So from this I am starting to assume it is a hardware only problem.
Likely PSU or Mobo from past experiences.