Step 1: Format the Drive
The steps here are to use the command line to format the disk properly using the diskpart utility.
[Be warned: this will erase everything on your drive. Be careful.]
The number of your USB drive will listed. You’ll need this for the next step. I’ll assume that the USB flash drive is disk 1.
5.Format the drive by typing the next instructions into the same window. Replace the number “1” with the number of your disk below:
create partition primary
select partition 1
When that is done, you’ll have a formatted USB flash drive ready to be made bootable.
Step 2: Make the Drive Bootable
Next we’ll use the bootsect utility that comes on the Vista or Windows 7 disk to make the flash drive bootable.
1.In the same command window that you were using in Step 1, Insert your Windows Vista / 7 DVD into your drive.
2.Change directory to the DVD’s boot directory where bootsect lives:
3.Use bootsect to set the USB as a bootable NTFS drive prepared for a Vista/7 image. I’m assuming that your USB flash drive has been labeled disk G:\ by the computer:
bootsect /nt60 G:
4.You can now close the command prompt window, we’re done here.
Step 3: Copy the installation DVD to the USB drive.