This is how you reset the password:
Reboot the machine:
From the console CTRL-ALT-DEL
If you've got GDM or a GUI installed, there's an option there to reboot. If not, CTRL-ALT-F1 to switch to a console VT and then do a CTRL-ALT-DEL as above.
Presumably you're using grub, so when the grub bootloader comes up, press any key to enter the bootloader. The default kernel should be the first in the list, so press to append something to that particular kernel entry.
Go to the end of the line and add '1' or 'single' to that entry. Make sure to leave a space between that and the previous word. Then press to exit that particular mode and 'b' should boot you up again.
You should be dropped into a root prompt. You can change the password by remounting / as read-write (as by default it'll be read-only) & running passwd
# mount -o rw /
# passwd root
# mount -o ro /
Reboot the machine again and your new root password is the password you set in single user mode.
Note: I don't think it's possible to go through the installation process without setting a password without some kind of custom kickstart script.