Cannot log on to Vista ultimate anymore! logon.scr screen error

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.

Thanks Zoron, when I do this Vista repair install will it delete all of my files? or just reinstall the OS?

Anyone have any other ideas?

Hmm looked up the instructions...says I need to be inside Vista in order to do this, this I can't get passed the stupid logon screen I can't get in to run the dvd

Thanks Zoron, I ended up reinstalling Windows Vista over my current files. It saved all the files under windows.old so it wasnt too bad. I'm up and running again. Thanks for your help!