How to separate windows users?

Question

vhd

Good afternoon!
Dear sysadmins, help with the solution of the issue.
Initial data, 1 computer - 2 users, mother and son.
Mom has enough office suite and a browser for her work, she doesn’t need a computer anymore.
The son needs everything except the office suite) a lot of games, with all kinds of cracks, game recordings, YouTube broadcasts. Now I got carried away with some kind of binary options ... dozens of tabs in 3 browsers, some kind of Chinese software all the time, a bunch of progs, other threshing floor-permanent viruses and other evil are dragging behind them. Let's leave the issue of education and restrictions to the guy's mom.
The essence of my question is how to divide their workspace? So that, regardless of the guy's "pranks", my mother had a working computer.
Simply creating an account in Windows does not help, since many programs are installed "for everyone". Now Windows is spinning on a 120GB ssd, there are 2 more screws 2TB and 250GB (an old one though).
Is it possible to roll 2 systems in isolation from each other, or maybe you need to use some kind of virtual machine?
UPD1 Is it possible to install 2 operating systems on VHD disks, thereby isolating them from each other? what are the downsides, performance?
UPD2 Or is it better to install the OS on a physical partition and the second one on VHD (without any virtual boxes and vmware). ?
Will it be possible to boot a second OS without booting the first one?

Answer 1

and it’s not easier for mom to install ubuntu, and leave Windows for her son