Why is my virtual machine resetting on boot/power off?

complete noob to this here. never used a virtual machine, but a program I wanted to build is super messy on windows, so yeah, hoping it's better on debian/mint

in any case, I start up the virtual machine... and its screen resolution has changed back(how do I get it to 1080p or 2.5k? it has neither option oddly...), there are no icons on the desktop, chrome is gone, and my installed software in general is gone.

is it because I kept the iso loaded in the virtual disk drive? when I remove it, it finds no bootable medium, so just taking it out won't work, I tried prioritizing booting from hard drive first, but that didn't work either.