Ubuntu Install - Error invalid arch-independent ELF magic

sudo fdisk -lu /dev/sda
sudo mount /dev/sda1 /mnt (if /dev/sda1 is the boot partition)
sudo grub-install --root-directory=/mnt           /dev/sda
sudo reboot

Enjoy your newly installed Ubuntu!

Windows 7: get pc serial number from command line

To get your machine serial number in Windows 7, you can try these command:
wmic bios get serialnumber or
wmic csproduct get identifyingnumber
Have fun without looking at the back of your pc to find the serial number!