Best answer by AjTrek1
When you download the app to a clean device (meaning the Sonos app was never present or it was deleted) you should get one of two options after if finds your Wi-Fi:
1. Join existing Sonos
2. Set up new
However, if as you say "the new laptop is using the wi-fi already" then as Alan_6 said you are not on the same network as your Sonos.
Chrome Books are not supported