I don't mean to be rude but this question has been answered many..many times in this forum. But here goes one last time.
Simply follow the directions in this thread. It's a self contained file that will wip your phone and return it to as about complete stock as you can get. read through the questions in the post and I'm sure any questions you have will be answered.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?