Few days back I installed Ubuntu on Machine which already had Windows installed. Yes your guess is correct thats basically "Dual boot". The issue I had faced was on machine startup it starts Windows only and not been able to access Ubuntu, which was installed correctly. I searched many forums and articles, then I came to know about re-installation of GRUB GRUB is a GRand Unified Bootloader. For more info, Please Visit: http://www.gnu.org/software/grub/ . So I thought I should share the info with all. Below are the steps required to perform. 1. Boot into the Live Ubuntu 9.04 CD 2. Open Terminal 3. Type command: sudo grub [This will give you grub> prompt/shell] 4. On Grub Prompt Type below commands on by one. find /boot/grub/stage1 [This will give you the location as result. In my case the location was (hd1,2)] root (hd?,?) [? = the values returned to you as result of above command] setup (hd?) quit That i...