I recommend you look into the CompTIA A+ certification. You can pay to do a course or just buy/borrow books that people have written on it. You can actually do the exam and become a certified geek or just read up on it and know all about it.
I did the course and had instructional videos by a guy called Mike Meyers (IT guy, not the actor guy) and it was really well done. Do a Youtube search for mike meyers a+ and you can see some snippets of them uploaded.
Also included in the course was the study guide book printed by Element K and I thought the content was pretty good as well.
This will knock off all of the basics for you and also some more advanced stuff. After this if you want more then you will need to specialise (i.e. security, networking, administration etc...)