What is this error - cannot boot to BIOS or Logo HP?

[Prométhée]

Hello
without further explanation ??

HP Engage Flex Pro-C Retail System - Maintenance and Service Guide

see if the model of the computer matches, and the sequence of beeps

https://support.hp.com/us-en/product/hp-engage-flex-pro-c-retail-system/22488604/manuals

[Ryan_Tran]

In my case, the power LED flashes/beeps Red five times (long flash/beep) and White seven times (short flash/beep).

Five long beeps are System board

What are seven short beeps? (I cannot found seven short beeps in your link)

[Prométhée]

the computer model may not be the right one.

please give the computer P / N product no.
and a little history of the before problem!

To find it follow this
for a desktop computer

HP Desktop PCs - How Do I Find My Model Number or Product Number? | HP® Customer Support

[Ryan_Tran]

Product No.: 5NZ17UC#UUF

When my client reported to me this PC turned off automatically while they were in use and then the PC beeped like my video. I went there and checked, the PC didn't output any error message or the HP logo on the monitor, also I can't access BIOS

[Prométhée]

sorry why do you say "my clients"?

[Ryan_Tran]

I'm a IT support of a company, I'm new

"my clients" mean my user. I'm used to calling users a client

[Prométhée]

is the material under warranty ?

I advise you to contact HP pro support