Fix for error, without reinstall.
There is a way to repair the lsass error without doing a reinstall.
The simplest way is to remove the hard drive and place it in another machine.
Scan it for virus/worms just to be sure.
Open the System Volume Information folder on the drive containing the broken Windows.
Browse down to the next to newest folder and then to the snap shot that is as new as you trust.
In hear you will find a set of registry files that can be copied into the system32/config folder to replace the corrupted registry.
This can also be accoplished from a linux boot disk as well as (I think) from the repair console (if you know the password)
If further details are needed let me know.
looney-bin