Thanks for the advice, I removed the pid from var/run and tried the -re-install option from Ambari and it worked !!!
All services are up and running now including Oozie.
One final question, I wanted the GUI interface that the sandbox offered, I was assuming Hue will be installed as a part of HDP2.0 stack, But doesnt look like.
Is this true ? Do I manually need to install Hue? is not included on HDP2.0 install thru ambari ?
I will open a separate thread for this.