After downloading the Ubuntu OS, I rebooted my computer (as recommended) and the computer went straight to an ID login interface- basically asking me to enter my 'user' password, which I do not know. It is not the same password for my windows 7 account, and i have tried several other combinations which also do not work. I can login as a guest but cannot access any of my saved material. Please help me out.
Hold the Shift key when the computer starts to reboot. This should give you the grub menu. The second entry on the grub menu should be to boot Ubuntu to recovery mode. Select it and press the Enter key. This will eventually lead to a text menu with several choices, one of which should be Root Prompt. Select that and press Enter.
Now, run "passwd username" where username is the name of the account. Enter the new password and enter it again when prompted. Then run "reboot". Login using your new password.