11gR2 didn't ask me to set username or any password I have installed Oracle 11gR2 (latest version 11.2.0.1.0) on my system. During the installation it didn't ask me to set username or any password. I'm unable to start sql plus because i don't have the username and password.
Can anyone tell me what is the default username and password or what is the default password for SYS or SYSTEM?
Thanks
If the Universal Installer included with 11gR2 did not ask for a password, it is likely that the option to create a database was not selected during installation. 

Solution? Create a database with the dbca tool and supply a sys password when prompted. 

With older versions, perhaps including Oracle Database XE (11g), you might have luck with one of the default password combinations of sys/change_on_install or system/welcome1 or system/manager. On engineered systems I have also seen sys/welcome1 and sys/changeme