Boot Bios Setup Hang - Can Anyone Help Please?

HP Z400 Workstation. PN FX625AV
Have used the HP Support Assistant which reports BIOS has latest update.
About 1.5 years ago I installed a SSD for Windows boot but this does not seem to be the problem because once I press F9 and get the boot menu then everything is fine.

MSINFO32 reports BIOS as 786G3 v03.57 13/07/15.
BIOS Mode Legacy.
Windows 10Pro, 10.0.19041 Build 19041.

Problem1 started with BIOS Hang at "AHCI BIOS installed" prompt.
Workaround was Power Down by holding button in till it died.
Remove power lead from back and press power button again.
Start again and Press F9 to go to Boot Menu which gives the alternative of USB or HardDrive.
Choosing Hard Drive worked and it would boot into windows.
Tried resetting the CMOS by pressing the button on the motherboard for 10seconds.
CMOS was reset so had to change a few things and save in the setup.

Problem2, BIOS hang at "AHCI BIOS installed" prompt.
F9 is the Boot and F10 is the Setup option.
Restarting and pressing either F9 or F10 results in the BIOS returning either BOOT or SETUP but then hanging with a blinking cursor.

Computer is fine if it is left on Sleep but if it is Hibernated overnight with power removed similar hangs occur.
Currently the only way found to fix the hang is remove power as above - hold the button till it dies - remove power connector wait for minutes.
Restart and F9 seems to work to get the boot menu into Windows.

 

I always disable sleep and hibernate modes on client systems.

As the Administrator of your devices, you should keep control manually.

Your either on them, or your not!
Servers are a different tale

 

Thank Replicator for reply.
Don't want to disable Sleep as box is used intermittently all day but often not used for 4hours at a time.
Would have to keep removing USB backup drive to restart every time.
Have set Hibernate to Many Hours > 1day so it wont work unless selected.
Power is removed at night.
Computer still fails boot if it is restarted with the USB drive plugged in.
Have not tried it with both Sleep and Hibernate disabled and drive plugged in.

Removed USB drive from computer and it starts.
Is there any way of switching this off?
My Z400 says it only supports Hard Drive and CDROM.
Have tried to find something in the setup F10, the MBA Configuration Menu Cntrl S, and the Intel Matrix Storage Manager Cntrl I to switch off USB.

Wierd that the start is intermittent when the USB drive is plugged in but appears OK without the USB drive when the box BIOS does not support USB drive.

 

Yeh well, I would shutdown correctly after use.

It makes no sense to have a selected hibernate sched, if power is removed at night?

I do not know your system, or your intentions for it.

Give it a run