For Windows XP, going to the dos prompt and typing format C: won't work any more. You'll have to go into My Computer, right click on your C drive, and do a full format. If that won't work, get out your Windows installation CD, boot up to it (you may have to change bios settings to have your CD drive boot first), and have it format your computer when it prompts you to. As for putting linux on your computer afterward, if you're not ready for a real project (and have another computer that you can use to get support from forums online), just stick with Windows. I would also recommend FireFox from Mozilla, it helps you avoid popups, spyware, adware, and all sorts of other internet annoyances.