How To Install Windows Using An USB Flash Drive

Step 1: Open a command prompt with administrator privileges by clicking on the Start button, then type cmd in the search box and press Ctrl+Shift+Enter.

Step 2: On the command prompt, type diskpart to enter the diskpart utility.

Step 3: At the DISKPART> prompt, type list disk.

Step 4: Type select disk 4, where “4″ is the number of your USB flash drive from the list.

Step 5: Type clean to clean the USB flash drive.

Step 6: Type create partition primary. This will create a partition in the USB.

Step 7: Type active, to make the partition active.

Step 8: Type format fs=fat32 quick to format the USB flash drive quickly in the FAT32 file system.

Step 9: Type assign to have Windows assign a drive letter to the drive. Type exit to leave diskpart and type exit again to close the command prompt.

Step 10: Insert your Windows 7 disc into your computer and copy all the files to the USB flash drive.
U can see my screenshot:

After all files copied, insert the USB into a computer and boot it up to start Windows installation. Make sure that the BIOS is set to boot the USB flash drive first. On some computers, you can press F12 key to set boot options.