I had installed Ubuntu 12.04 on a separate partition, in ext4 format in my comp, which initially had only Windows 7. I had done the installation from a Live USB, which gave me the option Install on boot, in a GRUB menu.
I had chosen the option of "Installing Ubuntu alongside Windows". I had chosen the particular partition during the install, and in mount part, I had given
And I chose my only hard disk drive as the location to install the bootloader. The whole install process was over, and I was asked to restart, and while doing to it asked me to remove my installation media, which in my case was a Live USB.
I acted accordingly and removed it. While booting however, it booted directly in Windows, and no menu or option came for me to choose from both.