dvd rom does work, locked out !!!!

Pavillion ze1110 1k Mhz, 256ram, 20g hd,CPU mobile AMD Duron.. was joing a domain at home, everything was ok, downloaded some screen saver!!!bad move and when I came back the screen saver was on but the log on to windows dialog box was on and the user name was OWNER. The cancel button is grayed out and I tried every password but no luck. I tried leaving user name as OWNER and leaving password blank, this started to log me on, I could see my backgroud but then it automatically logs me off??? Nowmy CDROM does not work even in dos?? Any Ideas?