Install Windows 7 from USB Disk

Today, I tried to install Windows 7 Ultimate on HP Mini 210 edition. It so difficult since HP Mini has no optical drive included. How could I install this OS? Ah, finally I found an alternative way to install it and I want to share it in this article.

All you have to prepare for this project is a Windows 7 DVD Installer, a flashdisk at least 4gb, and another computer running with Windows 7 OS that has optical drive included or external DVD-ROM.