I am getting 6 beeps and flashing Red light on startup without any Display on my screen

[IceBoyTech]

I did go into the BIOS and enabled Secure Boot, unfortunately for me, after the change I can't get pass the series of six (6) beeps to undo my mistake.  I have tried resetting the CMOS by pressing and holding it for at lease 8 seconds, removing the onboard battery and trying all the PCIE slots on the MB.  All the online post I'm reading are telling me the same things I've already performed.  Any help would be greatly appreciated.   

Regard,

IceBoyTech

[Lil_Boy_Blue]

Hi

Page 90 onwards has some error code info...

https://support.hp.com/gb-en/product/hp-z840-workstation/6978842/manuals

http://h10032.www1.hp.com/ctg/Manual/c04823811

Surely physically dis-connecting the HDD would allow the system to give access to the BIOS again?

[IceBoyTech]

Thanks for your suggestion. I gave it a try but still no success. Will now review the provided link and update you later..

Regards, 

[IceBoyTech]

I've done all except for replacing the system board (4)

Power LED flashes red 6 times (once
every second), followed by a twosecond pause, and then the
computer beeps 6 times.
Pre-video graphics error. For systems with a graphics card:
1. Reseat the graphics card.
2. If the card requires external power, make sure the power
cable is properly connected.
3. Replace the graphics card.
4. Replace the system board.
For systems with no graphics card installed, the processor
may have no integrated graphics capability.