There were 2 roles installed on vCenter machine:
Active Directory Domain services
Lightweight Directory serivices
I removed both roles from Windows Server Manager (Add/Remove Roles), before proceeding it asked me to uninstall an instant of LDS from Add/Remove Programs. Once that instance is uninstalled both roles were removed. VMware Virtual Center server service couldnt start after reboot. Before proceeding the role removal i verified from our Primary Domain Controller, and this machine was not listed as a domain controller over there.
I am unable to login with default user as service couldnt be brought into running state.