Book on Windows Administrator User accounts, what do you suggest?

I am a manager trying to do 1000 things that we don’t have the staff for, and am looking for a book that will help me with some basic network questions, such as administrator vs user accounts on Windows XP machines. IT is not my main job but I have to handle it, as there is no one else that is any more capable. Any suggestions? I have purchased a number of networking books, and those seem to be much more than I need. Any websites where I can learn what I need to know?

Thanks.