Introduction
In this blog post I am documenting the procedure of how to install Windows 7 on a PC that doesn’t have a DVD drive, but a USB port using a USB memory stick. The blog post describes how to prepare the USB stick and boot from it. Once booted from the USB stick, the procedure of installing Windows 7 is exactly the same as installing it from DVD.
Things you need
You need a Windows 7 installation DVD for copying files onto the memory stick. You will also need a USB drive that is at least 4 GB big.
Procedure
Step 1: Get the Windows 7 installation DVD

Figure 1: Files and folders on the Windows 7 installation DVD
Step 2: Make the USB drive bootable
Stick the memory stick into a USB port and then open a CMD command prompt and run it as Administrator.

Figure 2: Open cmd command prompt as Administrator
In the command prompt type:
diskpart (This will start the DISKPART utility)
list disk (List the disks and identify e.g. by the size the disk id of the USB drive. In my case it is disk 2.)
select disk 2 (Select the USB drive)
clean (Cleans the USB drive)
create partition primary (Create primary partition on USB drive)
select partition 1 (Select the new primary partition on the USB drive)
active (Mark the primary partition on the USB drive active)
format fs=ntfs (Format the USB drive using the NTFS file system)

Figure 3: Diskpart example run
Next switch to your Windows 7 DVD. In my case it is the D:\ drive.
d: (Switch to D:\ drive)
cd boot (Change directory to the boot directory on the DVD)
bootsect /NT60 G: (This command creates the boot sector on the USB drive which has the drive letter G:\)

Figure 4: Bootsec example run
Step 3: Copy DVD files onto USB stick

Figure 5: Copy Windows 7 DVD content to USB stick

Figure 6: Done copying
Step 4: Booting from USB
The USB drive is now ready. Take it to the computer without DVD drive and plug it in. Reboot the computer and check during boot in the BIOS that the boot from USB option is selected. Next install Windows 7.
Have Fun!