How to install windows 7/8/8.1 os by pendrive

      To install OS by using pendrive before we must make a  pendrive bootable (or ) any other flashdrive  by without using any external applications only with command prompt itself.
as per following step must done properly to install os in pendrive.

Step 1:
     open the command prompt by
          start->accessories ->command prompt
          run  ->cmd

Step 2:
    In command prompt type  diskpart press enter.

Step 3:
      In diskpart select pendrive by  command select disk 1 becarefull while selecting the disk. The default disk hard disk is disk 0 .

Step 4:
      After selecting the type clean

Step 5:
     after clean the disk type the following command  create partition primary

Step 6:
     format pendrive in  ntfs file format for installing windows 7 and command is format fs=ntfs          quick  fs are stands for files system, ntfs are file fromat  quick  is the file formatting type.

Step 7:
     assign letter to drive by assign letter=k
     after assign letter type active. close the command
     prompt.

step 8:
     copy the all os file and paste the files in pendrive and Reboot your computer and  change boot options in bios  and install the  operating system. This following  step are also suitable for installing os in memory card also.