Amazon instance that does not have a volume attached as root (/dev/sda1) will not allow you to start the instance. Login to the AWS account and go to the Elastic Cloud Compute[EC2] section and go to Volumes (under the Elastic block store) then right click on your volume, attach, select your instance, then type /dev/sda1 in the textfield. Now you can able to start your Instance without any issues.
This blog is fully for system admins and others who are facing issues with their day to day IT life. Which helps you to learn from your mistakes and issues here you can find lot of troubleshooting techniques and other information which helps you to get some idea to fix your issues..