Is her system EUFI or BIOS?
I've noticed that on some systems with UEFI+Grub, if the system bypasses the UEFI boot screen and goes directly to grub, they have a tendency not to send the proper vesa resolutions and will end up in low graphics or even text mode. On these systems going through the EUFI boot screen and selecting Maui manually there will often times give you a better resolution for grub, AKA turn off fast boot.
If the system uses a BIOS instead of UEFI, and has an onboard GPU, I'd check the in the BIOS to see if there is some sort of initial VGA memory allocation setting.
I've noticed that on some systems with UEFI+Grub, if the system bypasses the UEFI boot screen and goes directly to grub, they have a tendency not to send the proper vesa resolutions and will end up in low graphics or even text mode. On these systems going through the EUFI boot screen and selecting Maui manually there will often times give you a better resolution for grub, AKA turn off fast boot.
If the system uses a BIOS instead of UEFI, and has an onboard GPU, I'd check the in the BIOS to see if there is some sort of initial VGA memory allocation setting.