There are many many such books on the market - I suggest you borrow a few from your local library and browse the shelves at PC World to find one that suits you.
There are the Idiots guides (The Complete Idiot's Guide to pcs, for example); The Dummies guides (Windows XP for Dummies) both of which are simplistic, use large type and lots of diagrams. They may be too patronising for your tastes.
I like Computer Active, a fortnightly inexpensive magazine that has many excellent features in plain English.
Whichever book you decide to buy, make sure it is the latest edition and relevant to your pc and operating system.