That is a regular users password it is asking for. On ubuntu root logins are disabled so you can't get in that way. I found on Google that Ubuntu has a recovery mode boot option in the grub menu. This may allow you to get into single user mode "init level 1" as root. Then use the passwd program to create a new password:
passwd <username>[ENTER KEY]

You will be prompted twice for the new password.

Then reboot and log in with your new password. If you also forgot your username, it is the same as the directory inside /home/:
ls /home/