Username and Password Issue

I have just installed Kali Linux 2.0 form a live USB, and have encountered a few problems.
When it reboots after installation and prompts for username and password, I entered what
I put at the beginning of the installation, but it won't work. I've attempted user root and
password toor, but that does not work either. Any help would be appreciated.
Thanks

You probably made a mistake typing your password during installation process. If you can't access you might have to consider a reinstall.