Just do it step by step. I left everything US this year and changing email accounts was definitely the most tedious. But in the end I took my time with it. Switching 3 accounts per day was alright. :) Just start with the most important accounts and change the others when you need them.

Whenever they say "... but I like Windows." I'm like: Ah so you like CandyCrush ads on your homescreen. Got it. Yeah who doesn't like to look at some ads first thing in the morning.