Really doesn't matter to be honest.
Click your start button and find "settings", click that and find "control panel", open control panel and find an icon labelled either "Add/Remove Programmes" or just "Programmes", click that open and let the computer populate the list. Scroll down and highlight the programme you want to DELETE, either Mozilla Firefox or Chrome. When you highlight it a box should appear saying remove hit that and it should remove the programme for you.
There are other way of selecting Chrome as your default browser but I can't do instruction for that because I don't have the right permissions to mess with the computers in work to sort the process. If you can wait till tomorrow I'll check at home and post or if someone else wants to do it the carry on.
It's pretty straightforward, good luck