Thanks to Basavaraj, Shubham and John for your replies.
I got my laptop refreshed for another reason and the new installation of AO2.2 SP2 on it didn't fail to launch.
@John -> I was aware of the AO issues inter compatibility issues with other plugins and tried disabling other plugins which didn't help me. I was unable to try your suggestion on the load behavior as I got my machine refreshed before that. I will try this tip if I hit this issue next time.(hope don't get this issue again ;-))
Thanks,
Santhana