Steps To Create A Bootable Pendrive
Open your PC's PowerShell or Command Promt with administrative rights.
After inserting your USB pendrive, run DISKPART from the PowerShell.
Type the command LIST DISK. The result will be as shown below:
Here DISK 0 is the hard disk and DISK 1 is the pendrive I have used.
In my case, the USB drive is DISK 1. So in this step, I enter the following command:
SELECT DISK 1. According to your disk number, the "1" in the command will change.
After the USB drive is selected from DISKPART, enter the following commands one by one:
Exit PowerShell and insert your Windows 7 installation disk. Now open 'My Computer'.
Note the drive letters of both - Your pendrive and Windows 7 installation disk. In my case, they are G: and H: respectively.