Hi moiz123

The same issue has been reported in the following topic Droplet not starting

To summarize, go to your Dashboard-> kernal tab and try mounting the recovery kernel. This should allow you to run your droplet in safe mode.

In regards as to how to repair the droplet, this will depend on what happened and what has been damaged.

There is some details on the bottom of this page
https://www.digitalocean.com/help/technical/backup/