1. Install gparted
sudo apt-get install gparted
2. Open gparted, format the U disk into ntfs (note to uninstall usb first)
3. Install ms-sys and download it here http://ms-sys.sourceforge.net/#Download
4. Unzip and Installation (use root when installing)
tar xvf ms-sys-2.1.5.tar.gz
cd ms-sys
make
make install
5. After installation, write the MBR to the U disk
sudo ms-sys -7 /dev/sdX
X Replace with your own drive letter example /dev/sdc not /dev/sdc1
6. Then copy the files in the windos 7 installation disk to the U disk and
reboot into the win7 installation disk