In my laptop initially it was Windows 7 and 8 to dual boot.The status of the partitions are "system" for win 7 and "boot" for win 8. Then I formatted win 7 which was the system partition and installed ubuntu 12.04 with windows 8 (I chose install ubuntu alongside with windows 8). Now it doesn't appear any list to select an operating system instead it directly loads ubuntu.
How to solve this?