I have an off the shelf Compaq that I am planning on installing a fresh OS on. This is to remove all factory installed software (plus adware and spyware). I was wondering how to best go about this. I have already backed up all of my files that I want to keep. Do I need to format my hard drive? If so, how do I do this and how do I then install the OS. Also, Should I get XP home or Professional? Thank you, Alex