Student or Learner
What does mean the underlined phrase?
But for most of us Ubuntu can replace Windows full-time. It offers a safe, dependable desktop experience that can run on and support a wide range of hardware. Software available covers everything from office suites to web browsers, video and music apps to games.
Yes, though not out of the box, and not with guaranteed success.
not a teacher
In this context, to say that something is functional "out of the box" means that it can be used immediately on installation, without requiring additional elements (e.g. a driver) or intervention (e.g. configuration) by the user. "Not out of the box" suggests that the buyer will have to do something extra to it before it will function properly when installed.