If you want to explore the SAM registry part, which is only viewable with the "Local System" account.
One way to gain access to the SAM and Security keys is to execute the registry.exe in the local system account. PsExec from http://www.sysinternals.com supports an option that enables you to launch a process in the local system account.
Download the psexec tool (freeware) from sysinternals.com and execute the following command with the help of cmd.exe:
psexec -s -i -d c:\windows\regedit.exe
Then browse to:
HKEY_LOCAL_MACHINE -> SAM
Another way to gain access, is to reset the registry security settings, but this will waken the system's security!
btw. the "Windows Internals 4th edtion" book has some chapters about login process and security.