Installing different version of windows in one computer may be needed to get one advantage that other version dont offer.
Usually the default boot loader version will be windows version that is installed last. This default boot loader however can choose which windows to load when the booting started. however, You can modify it through msconfig.

by using msconfig you can change default boot order in you windows PC

1. click windows logo
2. type “msconfig” in search form
3. in msconfig window choose boot menu
4. click the OS you want to set to be default OS to boot.