This question is very vague. I am going to assume you mean reinstalling windows on your laptop.
Did your laptop come with any install/setup CD/DVD's? If so, put it in, and reboot the laptop and boot from the disc. It will take you through step by step on the installation process.
Answered by qroberts on October 21, 2010.
When you want your main disk formatted:
Follow steps 1 - 5 from this guide, continue after that step if you do want to install an OS.
If you don't have a Windows XP CD but do have a Windows Vista/7 then the steps to get to the setup will be similar and even more user friendly.
When you want a second disk formatted:
Open Windows Explorer, go to My Computer and right click the Drive. Click Format an do it there...
Answered by TomWij on October 21, 2010.
I don't think a link to a different site for something as simple counts as a "real answer". That link could just as easily have been found by googling. I upvoted your comment to r0ca's comment because I believed you were right. But I also think your answer is only a half real answer. - Mussnoon on October 21, 2010
I'm correcting myself in the name of earlier decisions that had been made in a new comment to the question. - TomWij on October 21, 2010
Content from Superuser of Stack Exchange. Original article at Superuser.
Google it if you don't know it - r0ca on October 21, 2010
Not sure this question fits the FAQ - r0ca on October 21, 2010
@r0ca "Google it if you don't know it" That is what we are here for. I know the question is vague so we should just ask the op to give more information about what he/she is trying to achieve. - qroberts on October 21, 2010
To further what qroberts said: I understand superuser to be a forum for personalized discussion and on computer-related issues, something wholly outside of Google's scope and realistic ability. "Google it" is a very ill-conceived comment on this forum. - NoCatharsis on October 21, 2010
@r0ca might be right, an user [should do his homework](http://superuser.com/questions/how-to-ask) but "googling it" might not work out for the user. - TomWij on October 21, 2010
I believe this question was closed more because of the vagueness rather than because it was too simple. - Sathya on October 21, 2010
Googling itself is an art; to enter the right key words and find the right answer that is in simple words. Most of the times you get lost in various links that are thrown up. - Dheer on October 21, 2010
So if the user is unable to Google what he's looking for, I doubt he'd be able to format a computer properly just with some step-by-step guide provided by Search engine... For me, this question doesn't meet the FAQ requirements and this user ask a question that is to wide to answer. - r0ca on October 21, 2010
@ninny: Please read this: [How to ask.](http://superuser.com/questions/ask-advice) - Mehper C. Palavuzlar on October 21, 2010