It really a simple process to Create bootable Pendrive using command prompt
The first step is open command prompt with administrator privilege. Go to start search cmd, right click and run as administrator.
Type the following commands one by one in command prompt
Step 1 : Diskpart
Step 2 : List Disk
Step 3 : Select disk 1
Step 4 : Clean
Step 5 : Create Partition primary
Step 6 : Select Partition 1
Step 7 : Active
Step 8 : Format fs=ntfs
Step 9 : Assign
Step 10 : Exit
Step 11 : Go to your windows saved folder and make sure the bootsect.exe is present inside boot folder now copy the windows path and paste in your command prompt like this
J:\> cd windows7
J:\windows7> cd boot
Step 12 : After this step copy all the files from windows7 folder from your local disk to your USB Drive. Hope You did your USB drive as bootable using command prompt.
Thanks for your interest!