Site admin and users of a project are locked

Hi

Need urgent help.

We're using QC 9.0. After upgrading to Patch 26,

         - all the users of a project

          - and SiteAdmin user (only one user)

got locked and could not login.

please let us know if anyone could help.

I need to know

          1) How can I unlock the QC users of a project ( we knew the password)

           2) How can I unlock the SiteAdmin user.

We tried putting a blank password (NULL) at DB level, but even after doing that, we could not login with blank password into SiteAdmin.

please advice

thanks!