How To Boot And Install Windows 7 From USB Flash Drive.

The application that I am talking about is WinToFlash. This is a small application (only 2.1MB) that allows you to convert your Windows installer CD/DVD to a bootable USB drive. Not only is it easy to use (nearly idiot-proof and does not require you to have any technical knowledge), it is also fully portable – No installation is required and you can bring it wherever you are.
Preparation

Before you start, here are some stuffs that you need to take note of:

1. You need to have a USB drive of at least 3GB space in order to create a Windows 7 bootable USB drive.
2. The process will format and wipe off all your files in the USB drive. Remember to backup before you proceed.
3. You need to have a Windows 7 installer DVD and an optical drive to read the DVD. If you have only the ISO file (downloaded directly from Microsoft), you can use Virtual Clone Drive to mount the ISO in your computer.

Installation:

• Download WinToFlash
•  Put in your Windows 7 installer DVD and plug in your USB drive.
• Unzip the folder to your desktop and run the WinToFlash.exe file
• Some of you might see the “WinToFlash DLP_NotFound” error message. You can safely ignore this error message.

• On the main screen, click on the Window Setup Transfer Wizard. This will bring you to the wizard mode where it automates (almost) the whole process for you.

• On the next screen, there is an option for you to go into the Advanced mode and tweak some of the settings. You can ignore that (if you are not into tweaking) and click Next to proceed.

• Point the Windows file path to the Windows Installer DVD directory.
• Point the USB drive to the USB directory.

• Click Next.
• Accept the agreement.

• Preparing your USB drive. Make sure you have backup all the important files before you proceed. This will erase all your data.

• Transferring in progress. This might take a while. Go for your coffee break.

• Once you see the following message, the whole process is done. You can now boot Windows 7 from the USB drive.

Some computers require you to change the bootup setting in the BIOS before you can boot from USB. Look into your motherboard/computer manual for more instruction.

Very smooth guide to create a bootable win7 (or vista and xp) to usb drive (tested).