Things you needed:
. A USB Drive, Minimum of 4gb.
. Windows 7/Vista Setup Files.
1. Plug the Pen Drive into your Pc.
2. Note the letter of the Pen Drive from My Computer.
3. In the Start Search Box Type cmd and Press Enter.
3. In the Start Search Box Type cmd and Press Enter.
4. Now, type diskpart in the command prompt, a new window will open as shown in the image.
6. Now type the following commands one by one and hit enter.(It is assumed that your USB disk
is Disk 2, if it's Disk 1, use Disk 1 in the command).
SELECT DISK 1
CLEAN
CREATE PARTITION PRIMARY
SELECT PARTITION 1
ACTIVE
FORMAT FS=NTFS (Formatting may take a few minutes. Be patient.)
ASSIGN
EXIT (Now the disk partition program will exit, now we need to give some more cmmands.)
7. Insert the Windows 7 Installation DVD in your optical drive and note down the Drive letter.
8. Here i am assuming DVD drive as "F" and USB drive as "K".
9. Now type F:CD BOOT and Hit Enter.
10. Next type BOOTSECT.EXE/NT60 K: where K is the USB drive letter. This command will update
the drive with BOOTMGR compatible bootcode
11. Now exit the command prompt and copy all the files from the windows 7/vista DVD in the USB drive.(Just make sure you dont cause any errors)
12. Now Enter the Bios system accordingly by pressing the delete key.(This may vary some times it will be F2 or F12. It depends on the type of your system. Any how during the Startup, your system will display which key to press to enter the Bios).
13. Now Select the USB/ Pen Drive as the first boot driver.(Set the first boot priority to USB drive.)
14. The computer will boot from the USB drive and the installation will begin as normal. :-)