I'm writing this to show people how to take a standard flash drive and make it bootable. I mainly am just writing it here because I want to be able to find this again easily later. Here we assume that you are using either Vista or Windows 7 to create a bootable flash drive.
1. Insert your USB (4GB+ preferable) stick to the system and backup all the data from the USB as we are going to format the USB to make it as bootable.
2. Open an elevated Command Prompt. To do this, type in CMD in the Start menu search field and hit Ctrl + Shift + Enter. Alternatively, navigate to Start > All programs >Accessories > right click on Command Prompt and select run as administrator.
3. When the Command Prompt opens, enter the following command:
DISKPART and hit enter.
LIST DISK and hit enter.
Once you enter the LIST DISK command, it will show the disk number of your USB drive. In the below image my USB drive disk no is Disk 1.
4. In this step you need to enter all the below commands one by one and hit enter. You can easily guess what these commands do as these commands are pretty self explanatory.
SELECT DISK 1 (Replace DISK 1 with your disk number)
CREATE PARTITION PRIMARY
SELECT PARTITION 1
(Format process may take few seconds)
DonÃ¢â‚¬â„¢t close the command prompt yet as we need to execute one more command at the next step. Just minimize it.
5. Insert your Windows disk that you will be copying the files from and note jot down the drive letter of the optical drive and USB media. Here, I use Ã¢â‚¬Å“DÃ¢â‚¬Â as my optical (DVD) drive letter and Ã¢â‚¬Å“HÃ¢â‚¬Â as my USB drive letter.
6. Go back to command prompt and execute the following commands:
D: and hit enter. (Where Ã¢â‚¬Å“DÃ¢â‚¬Â is your DVD drive letter.)
CD BOOT and hit enter
(Where Ã¢â‚¬Å“HÃ¢â‚¬Â is your USB drive letter)
7. Copy Windows DVD contents to USB.
You are done with your bootable USB. You can now use this bootable USB as bootable DVD on any computer that comes with USB boot feature (most of the current motherboards support this feature).
Note that this bootable USB guide will not work if you are trying to make a bootable USB on XP computer.
Note: This post is from here.