Debian10 Username and Password

I gave this computer to a client a while ago and it has been working well for them up until this point. Every time we boot it up it brings me to the selection menu. After making the selection it freezes on one of two screens 

I got it through once, though I let it sit for a bit then starting it again and it has frozen again

That should be an issue with the DE/File explorer, no idea what XFCE uses for those, and no idea how to fix it.
For Mate, there is a hidden DE settings file that should be deleted and after reboot it works.
Try searching Debian XFCE forums with search terms:
desktop shows with no icons and no task manager

I couldn’t seem to find anything there that approached my issue. I switched computer towers entirely to see if that was the issue and it’s not. It’s not letting me though at all again though. This is a calibrated machine so I don’t want to ruin anything.

I don’t have many options within the boot menu.

they won’t let me into register a profile for the Ubuntu forms because I don’t know what this outputs

date -u +%jXfce|sha256sum|sed 's/\W//g'

this is my start up screen
 

Try hitting control-Alt-T
It should open a terminal window

Then try 
rm -R ~/.cache/sessions/*
Logout and log in again without rebooting.
Hopefully it's fixed
Ref:  askubuntu.com/questions/451847/desktop-i...click-on-the-desktop

I vaguely remember having this happen once years ago.

I got in and I’m leaving it on so it doesn’t freeze again. Though when it freezes at that screen I can’t do anything at all. I can’t even restart it.

since I’m in I can open the terminal and try that

This is a calibrated machine so I don’t want to ruin anything.

The least you should probably do is backup your machine config folder to some external device, if you haven't already done so.

Copy the config folder to a USB stick.

Yup I was able to do a backup

I tried what you suggested and it too me to a login page. I’ve never set a password for this and apparently they have not either. I know there’s no default password but it won’t let me log in with nothing added

so I had to reboot and it of course won’t let me into the terminal on boot menu