how to make a pendrive bootable without using any third party software

In this tutorial we will teach you how to make a pendrive bootable. Suppose you have lost windows(the most common problem these days) and dont have a CD or a DVD but you have a soft copy of the O.S. somewhere else. Using this tutorial you can use that soft copy to install windows on your PC without using a DVD. We do it just by using a pen-drive , that is the most common component people have today. Using the method explained below you can install windows using your pen-drive. Using this method you can install windows 7 on your laptop or PC directly from the pen-drive.
Note: the pen-drive must have a storage capacity greater than 4GB for this tutorial to work.
Throughout this tutorial you will learn to automate the process of bootable pen-drives.

Go to any of your friends PC with windows 7(If you have lost your windows) and Just follow these steps:

1. Format the pendrive in the NTFS format first.
2. Go to start menu and type command prompt in the search box.
3. You will see command prompt(the one with the icon of a black windows screen) in the search results.
4. Right click on command prompt and select "Run as administrator".
5. A Command prompt window will open.
6. Now type the following commands in the command prompt window.
7. Type diskpart and press enter.(This is done to open disk partition program)
8. Type disklist (this shows the list of disk drives - pendrive is also included in this list) and press enter.
9. In the list of all the drives being shown on the command prompt screen, locate your pendrive and just note down its location - lets say its location is 'X'.
10. Now type SELECT DISK X (Note X denotes your pen-drive location) and press enter.
11. Now type CLEAN and press enter.
12. Type CREATE PARTITION PRIMARY and press enter.
13. Type SELECT PARTITION X and press enter.
14. Type ACTIVE and press enter.
15. Type FORMAT FS=NTFS and press enter.
16. Type ASSIGN and then enter.
17. Type EXIT to exit the disk partition process.

Now insert the windows DVD in the DVD drive or if you have an iso image of your windows, jsut mount it on any of your virtual drives(Read this post, if you dont know how to do this). Note the name of your DVD drive as well as Pen-drive. In general we have the DVD drive name as G and the Pen-drive name as I. Replace this G and I accordingly as per your system config, in the steps below:

1. Type G:CD BOOT ->press enter.
2. Type BOOTSECT.EXE/NT60 I: and hit enter. (This is done to update your pen-drive with the bootmgr code)
3. Now copy the content of your windows DVD or the iso image on your virtual drive to this pen-drive.(Be cautious: Don't commit any mistake during this process.)

You are done now, you have a bootable pen-drive ready to install windows.