Keychain access serious problems

Suddenly my MacPro with Snow Leopard no longer accepts my login password.

As suggested I booted with my original System DVD, pls NOTE my current system is SL 10.6.8 while the DVD has a SL 10.6.2

Created a new password and I can now log in with the new pass

However I am unable to use the login keychain application as the application rejects the new pasword and the original password I used before being unable to log.

Also none of the methods suggested in the Help menu in the Keychain app allow me to use it.

I am not sure if this could be the reason for the problem could be the difference between the installed system and the original dvd Password reset utility.

How can I create a new password allowing me to log in and use the keychain app.

In this world with million passwords is a real disaster for me.

Also using Web-Confidential Utility doesn't work

Is there a way maybe through Applescript or some other trick to get a text file with the content of my Keychain?

Thanks a lot to anyone who will help

Etnad