I’m not sure that I agree that low-contrast text in the top panel is friendly to old people (or anyone, for that matter). Text that contrasts with the background is way easier to read and strains your eyes less.
I would hate to use this desktop, it’s a pain in the ass to even read the clock in the top corner. I don’t even have vision problems.
I really like Debian. There’s a version of Linux Mint called Linux Mint Debian Edition (LMDE) that I recommend for people new to Linux. My wife has been using it for about 6 months.
The easiest way to install is by using the live image on a USB drive. I recommend installing Ventoy on the USB first if you like the idea of having a dedicated USB for boot images. Totally not necessary, but can be useful.
I’m on my second install now. I fucked up the first one pretty handily by accidentally wiping the boot partition in gparted. (Like a complete idiot, because the partitions are labeled.)
So I think that there may be a BIOS misconfiguration here somewhere. Try looking at the answers here, maybe one of them will help: https://askubuntu.com/questions/708247/cant-boot-into-ubuntu-in-windows-10-ubuntu-dual-boot
You replied to the wrong person.
ACPI errors shouldn’t be an issue, it’s somewhat common to see them. Are you still able to boot from live USB? Are your Linux and Windows installations on the same drive? Sometimes Windows can mess with the boot settings of other OSes and even break a GRUB install.
The picture you posted doesn’t show an error, that’s a screen to select your boot drive. Are you saying you don’t know how to select a boot drive or that when you do select the boot drive, nothing happens? You’re not giving us any information to help you with.
LXQt or XFCE if I have to pick a DE. Fluxbox or openbox if I can get away with just a WM. ;)