You will need at least a 4GB USB key to fit the entire contents of the Windows 7 DVD.
So the next thing you are going to need to do is format this disk using DISKPART.
Follow the steps below:
1. Insert the Windows 7 DVD into the optical drive on your computer.
2. Insert the USB drive and make sure you can see it in explorer.
3. Run DISKPART – I’ll use screenshots to explain the rest of the steps.
* At a command prompt type DISKPART
* Now before you do anything else make sure you have inserted the USB drive and you can see it in explorer.
* Type LIST DISK to see a list of available disks
* Type SELECT DISK 3 ( in my case it happens to be disk 3)
* Type CLEAN which will wipe the disk
* Type CREATE PARTITION PRIMARY
* Type SELECT PARTITION 1
* Type ACTIVE to make this partition the active partition.
* Type FORMAT FS=FAT32 (wait for it to get to 100% complete)
Type ASSIGN so a drive letter gets assigned in explorer.
Now you should have a USB disk ready for the Windows 7 source files.
If you have the DVD load that into your DVD drive and copy the entire contents to the root of the USB drive.
Once that is done you will have a bootable USB disk ready for you to build your machines much much faster with Windows 7.