Vista Ultimate Upgrade SP1: Login Process has failed to crate security Options Dialogue

After a recent upgrade I was faced with a magnitude of problems but have
solved all but one. Often when i boot up I am greeted with "Login Process
has failed to created security options dialogue". The computer remains
stuck on a black screen and is non-responsive.

I did alot of research on this and so far I haven't found an answer. I can
bootup to Ubuntu when I have these problems but Vista is my preferred OS and
I consider Linux a backup.

Any ideas, I have:

Switched Sata connections
Checkdisked all drives

RR