This is a personal computer or PC. The concept from day one is that if you are at the keyboard, it's yours.

OK, try the old LIMITED USER and beef it up with NTFS PERMISSIONS. This is NOT an offer to write tutorials on either but between the two you have a fairly limited user that can't delete files that are not theirs.

In closing, let's say they broke the machine. Or the hard drive failed. Are you ready? I find 98% of owners are not.
Bob