How to make USB key

Quotes denote the command to type, do not type the actual "s
Launch the DiskPart utility by typing "diskpart" at the Start Menu.
"list disk" //command to find the drive with appropriate size.
"select disk 1" //where the "1" is actually the corresponding number of your USB drive.
Make sure you choose the correct flash drive if you have more than one of the same size.
"clean" // removes all partitions
"create partition primary" //bootable partition
"active"
"format fs=ntfs quick" //can use fat32 if all files on drive are something like 3gb or smaller.
You should not need a boot sector on a usb drive.  Most motherboards allow booting to usb drives.
"assign" // command gives the USB drive a drive letter, making it easy to access from Windows Explorer

You are done with diskpart, type "exit" //dont need quotes

Then you can copy everything from the Windows 7 installation DVD onto the USB key (a simple drag and drop will do).
I would not reccommend extracting directly from iso to flash drive.  It will take forever, and burn up your drive.
Instead, extract to hard drive first, then copy or cut/paste to the drive.  Make sure you do not put the files in a subdirectory or
the drive will not boot.

when installing from USB boot and enter bios setup (usually del key on bootup)
Find where it lists the hard disk boot order. (usually some kind of boot section)
Select hard disks and put the usb drive at the top of the queue with the c drive you install to just below it.
Save and exit bios (usually f10)

The installation will now proceed as usual—but faster.
You can remove the usb flash drive after the first setup reboot, it won't use it anymore.