Thanks LDBrwn_DBA.

I had come across a document related to SSO stating that you could use the Oracle Admin Assistant for Windows.

What I had done was go into the Oracle Admin Assistant for Windows and added myself as a user with my domain name under OS Database Administrators and OS Database Operators. Also under the Databases section I had selected this user and added some rights/privs/permissions etc.
Within the database I had created myself as a user using my domain name.

Once this was done I went to the command prompt and typed sqlplus /@db and when I did the show user it listed my domain name.

Upon doing further research I thought there were other Oracle pieces that were needed like Oracle Advanced Security for one. Then further reading showed possibly a directory server needed to be set up. I couldn't find anything that definitively stated for SSO you need exactly these pieces.

So thanks for letting me know the 2 pieces that are needed and I will take this and have a real attempt at setting up SSO. And for the notice about configuring the legacy app to use LDAP for account validation.

I'll let you know how I get on.

Regards,

pengwen