If you did not create a user account in the firstboot screens, switch to a console by pressing Ctrl+Alt+F2, log in as root and use the password you assigned to root.
If you cannot remember your root password, boot your system as
Once you have booted into single user mode and have access to the
# prompt, you must type
passwd root, which allows you to enter a new password for root. At this point you can type
shutdown -r now to reboot the system with the new root password.
If you cannot remember your user account password, you must become root. To become root, type
su - and enter your root password when prompted. Then, type
passwd <username>. This allows you to enter a new password for the specified user account.
If the graphical login screen does not appear, check your hardware for compatibility issues. The Hardware Compatibility List can be found at: