Can´t log in as root HELP?

Hi list! I was told that I´t wasn´t good to alow root logins (I´m new to Suse). I then used YAST to click ~"don´t alow root logins" thinking I would be able to "su" when I needed to be root. I then found out that "su" doesn´t work so I tried "sudo" instead, but that doesn´t work either. Is there any way for me to enter my current system as root now/again? or Do I have to format the hd and install a new system? (I have Suse 10.0) /Peo