"Access Denied" in Winodws Recovery Console.

My Laptop does not start WINDOWS XP.  Windows\System32\config\system registry is corrupted. I am trying to recover using orginal setpu CD using windows recovery console. However, once I get the prompt  C:\> most of the commands does not work - I can use DIR command. But can not "cd" to any directory. I get message "Access Denied"

Note: while invoking recovery console, I was not asked to select any installed OS and also not asked for password.

Any idea how I can resolve the access denied issue?

Thanks,

Bhameera