Windows UPDate

I am running windows XP All of a sudden, when I try to access windows update, I get an administrative only message, where I would have to log in
with a password. I am an administrator and never set up an password. I have tried everything, giving everyone permission through the registry, using disk clean up. I followed all steps on the microsoft site. It seems as though some active x files are corrup. I can't download new files unless I am able to access windows update.