You may find it helpful to read our articles on Windows security and password recovery examples. Video section contains a number of movies about our programs in action
Domain cached entries are stored encrypted in HKEY_LOCAL_MACHINE/Security/Cache registry key. While the decryption key resides in LSA secrets under NL$KM name.
Looks like your PC contains no cached credentials because the LSA secret was not found. By the way, on some OSes the Security/Cache keys holds empty entries (ones filled with all zeroes).