Recently I bought "asus k55vd-sx313r". Earlier I am using Lenovo G570. I installed Ubuntu 12.04 in Lenovo by choosing "Something Else" option, Keeping 2 Gb for Swap 10Gb for Root And 5Gb for Home. After Restart normally windows is opening, but Ubuntu is not detected. Even though hard partitions remain a new drives 10gb and 5gb.
Open the terminal and run the following commands
sudo add-apt-repository ppa:yannubuntu/boot-repair sudo apt-get update sudo apt-get install boot-repair After completing the installation you can launch it from System->Administration->Boot-Repair menu if you use Gnome, or search "boot-repair" in the dash if you use Unity
It is a old method ....