Logon.scr application failed to initialize properly in Vista Ultim

Greetings all,

I'm having a terrible time with my ultimate Vista machine. It boots up and
after a black screen appears for about 6 minutes finally the logon screen
appears. I see the icons for both of the user accounts but when I click on
them, nothing happens it does not allow me to enter a password. You can tell
in the background its doing stuff. I've let it sit this way for a day.
I've also booted into safemode with the same event, except I get the
logon.scr application failed to initialize properly, and then the screen goes
black.

I've booted to the Vista cd, and ran a repair which told me I need to
disconnect any camera or music devics (everything is disconnected)
I also restored to a very early point- still same problem
I've run memory diagnostic- still same problem- memory is ok.

I can't get into my machine! I really need help getting passed this.