No single book exists - plus by the time a single book is printed some aspects are obsolete.
I would narrow down the PC world you are going to be required to maintain and search for those topics on the web.
Youtube can be good.
From how to's
https://www.youtube.com/watch?v=SFowSc5gOhE
https://www.youtube.com/watch?v=SFowSc5gOhE
to general areas - basics on Windows 7
https://www.youtube.com/watch?v=odLZiGf-6bY
What's nice about this vid is that the guy is running it on a Mac. So if you had BootCamp or Parallels VM you could get some experience that way, too.
Good luck in your new job!