This is a quick and effective guide to create a bootable Windows 7 or 8 USB pen drive.
Requirements:
- USB Flash Drive with 4Gb minimum capacity
- Windows 7, Windows 8 or Windows Vista installation files
- Motherboard that supports booting fom USB
Steps:
- Plug-in your USB flash drive to USB port. Make sure you its contents are backed up.
- Open Command Prompt with admin rights either by typing cmd in Start menu search box and hit Ctrl+ Shift+ Enter, or going to Start menu > All programs > Accessories, and right clicking on Command Prompt and select Run as administrator.
- Type in the following commands in the command prompt:
First type DISKPART and hit enter to see the below message.
Type LIST DISK command and verify the Disk number (ex: Disk 4) of your USB flash drive.
Type SELECT DISK 4. In my case is Disk 4, which has 4Gb, as you can see in the following screen. If you have Disk 1 or any other number as your USB flash drive then use Disk 1 in all examples.
- Continue seting up the USB flash drive with the following commands. Press enter after typing each command.
SELECT DISK 1 to select target drive.
CLEAN to clean the drive.
CREATE PARTITION PRIMARY to create primary partition in drive.
SELECT PARTITION 1 to set primary partition.
ACTIVE to activate primary partition.
FORMAT FS=NTFS to format the partition. Formatting took a few minutes in my case.
If all goes well this far, you will have something like this:
- Continue with the following commands:
ASSIGN to assign drive letter or mount point.
EXIT to exit the Diskpart tool.
- Minimize the Command Prompt for now and insert your Windows 7/8/Vista DVD into the optical drive or mount your ISO backup, and take note of the drive letter. In my case, drive letter is “G” and USB drive letter is “J”.
- Go back to the minimized Command Prompt in the 4th step. Type the following command now:
G: CD BOOT and hit enter.Where “G” should be replaced with your DVD drive letter.
CD BOOT and hit enter.
- Type another command given below to update the USB drive with BOOTMGR compatible code.
BOOTSECT.EXE /NT60 J:
In the previous command, replace J: with your USB drive letter. If all goes normally you should have something like this:
- Copy your Windows 7/8/Vista DVD contents to the newly set up USB flash drive.
- Your USB drive is ready to boot and install Windows. When setting up, remember to change the boot priority at the BIOS to USB.
And that’s it, enjoy!
Just a small reminder guys. Just in case you haven’t done it yet, you should uninstall any Release Candidate builds (any build less than 6.0.6001.18000) before they expire on June 30th. After this date, the kernel will stop with an 
