Probably you had this problem at some point. You need a Win7 boot stick, but there's no computer with a inferior OS in sight. So here's how you do it under Linux.

• ~4GB USB Flashdrive
• Window 7 iso of your choice
• ms-sys (AUR: ms-sys; Source: ms-sys on sourceforge)

First reformat the stick as one big NTFS partition and don't forget to set the boot flag. Be aware this following command will delete /dev/sdX without questioning again! Check that sdX is your actual usb stick!

sudo parted --script  /dev/sdX mklabel msdos mkpart primary ntfs 1 100% set 1 boot on

then lets create a temporary directory to work in, create a mountpoint for the stick, the ISO and last but not least mount the iso and the Stick.

cd $(mktemp -d)
mkdir stick
mkdir iso
sudo mount -o loop ~/Downloads/myWin7Image.iso ./iso
sudo mount /dev/sdX1 ./stick

Now we can copy all Windows files to the Stick.

rsync -vPr iso/ stick/

After this we can simply unmount both paths.

sudo umount ./iso
sudo umount ./stick

Currently nothing would happen so let's use ms-sys from the same named package to write a windows bootloader onto the stick.

sudo ms-sys -7 /dev/sdX

That should be It! Now go and boot your inferior system and do what you gotta do.