lilin says

I tried deleting linuxdefi line and adding the pci=nomsi,noaer after quiet and that gave a KERNEL PANIC stuff and stuff
I tried adding it AFTER linuxdefi and it gave more KERNEL PANIC stuff

--
hardware name is Toshiba Satellite C855D/Portable PC, BIOS 6.20 01/09/2013
if thats necessary

Do not delete linuxdefi line, then your grub won't even recognize the partitions.

What this means is that the grub can't recognize the first partition of the disk either.

Could be a hardware issue: Make sure the hard disk is properly connected to the motherboard, and that the bootstrap is properly connected as well.

Otherwise, you may wanna run lspci-search and see if your motherboard supports GRUB bridge control ( ASUS motherboards often cause issues like that ).

If you identify issues like that, update your grub while its in quiet IRQ mode; via command line before full boot:
1. sudo vim /etc/default/grub
2. change GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=nomsi,noaer"
3.sudo update-grub

lilin says

I tried deleting linuxdefi line and adding the pci=nomsi,noaer after quiet and that gave a KERNEL PANIC stuff and stuff
I tried adding it AFTER linuxdefi and it gave more KERNEL PANIC stuff

--
hardware name is Toshiba Satellite C855D/Portable PC, BIOS 6.20 01/09/2013
if thats necessary

Do not delete linuxdefi line, then your grub won't even recognize the partitions.

What this means is that the grub can't recognize the first partition of the disk either.

Could be a hardware issue: Make sure the hard disk is properly connected to the motherboard, and that the bootstrap is properly connected as well.

Otherwise, you may wanna run lspci-search and see if your motherboard supports GRUB bridge control ( ASUS motherboards often cause issues like that ).

If you identify issues like that, update your grub while its in quiet IRQ mode; via command line before full boot:
1. sudo vim /etc/default/grub
2. change GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=nomsi,noaer"
3.sudo update-grub

I tried deleting linuxdefi line and adding the pci=nomsi,noaer after quiet and that gave a KERNEL PANIC stuff and stuff
I tried adding it AFTER linuxdefi and it gave more KERNEL PANIC stuff

--
hardware name is Toshiba Satellite C855D/Portable PC, BIOS 6.20 01/09/2013
if thats necessary

Linux boot order:
Bootstrap -> MRU -> GRUB -> Kernel -> Init -> System

Your issue is here:
GRUB -> Kernel

The grub has no idea whats the kernel IRQ handle, and has no alternative boot options


What you wanna do is disable MSI ( IRQ parent ) boot and see if the GRUB can just boot via the first disk partition ( which it should on GRUB vers. 4.45 and higher like yours ). That is done like explained here:

https://forum.manjaro.org/t/no-irq-handler-for-vector/66441

Copypasting:

When you boot, while in the GRUB menu and you selected to boot the installer, pres e and add, to the kernel parameters line, this pci=nomsi,noaer
You can place it right after quiet.
Then press F10 to continue booting. You might have to do the same once the system is installed and you boot from it. Look on how to permanently add boot flags to boot.