Won't boot after iTunes/Security update

[adrian2043]

After successfully updating to Sierra today, I then updated iTunes. When re-starting , there was no progress beyond the Bios entry screen. Nor can I can't enter Bios. I've also tried booting from my original Yosemite installation USB with no success (in safe mode or otherwise).

Currently I have disconnected all peripherals except Dell display via DisplayPort and an Apple USB keyboard.

Up until now I've had no issues with my year old Customac

 

[Jithin.C.V]

After successfully updating to Sierra today, I then updated iTunes. When re-starting , there was no progress beyond the Bios entry screen. Nor can I can't enter Bios. I've also tried booting from my original Yosemite installation USB with no success (in safe mode or otherwise).

Currently I have disconnected all peripherals except Dell display via DisplayPort and an Apple USB keyboard.

Up until now I've had no issues with my year old Customac

If it is getting stuck on BIOS screen, that could be another issue related with BIOS/Motherboard,etc

OS X and it's software updates will not make any changes on BIOS.

 

[adrian2043]

And how would updating iTunes affect BIOS?

 

[adrian2043]

I was thinking that none of the USBs were working because of no Caps Lock light on Apple USB Keyboard, but Apple USB mouse lights up when connected to keyboard. Could the USB ports still provide power but not data?

Not sure where to go from here.

 

[Jithin.C.V]

I was thinking that none of the USBs were working because of no Caps Lock light on Apple USB Keyboard, but Apple USB mouse lights up when connected to keyboard. Could the USB ports still provide power but not data?

Not sure where to go from here.

Try resetting BIOS.

 

[adrian2043]

Upon startup I get this screen.

As I mentioned in original post, I can't access BIOS settings as there is no response from keyboard so how would I reset?

 

[Jithin.C.V]

Upon startup I get this screen.

As I mentioned in original post, I can't access BIOS settings as there is no response from keyboard so how would I reset?
View attachment 224594

Check motherboard manual and find out location of Jumpers for resetting BIOS parameters.

 

[adrian2043]

Thanks. I had a brief look at Asus mobo manual after last post but but will check out again.

 

[AndersSF]

Did you fix this? I'm a bit sceptical about updating iTunes myself.

 

[adrian2043]

No.

This came up when I googled "Reset BIOS". Tried a couple of times with and without battery to no avail.