Winlogon process stays at 99% CPU usage forever.

i just updateded and installed the windows service pack
2 . When i rebooted my computer all it did when it loaded
my profile was sit there frozen. when i looked at the
taskmgr the winlogon process was taking up 99% of my cpu
usage. also it never stops.
If i go in safe mode under my profile kiel an
administrator still nothing loads and the winlogon process
stays open. But if i wait long enogh and open taskmgr,
explorer. then eventually i can atleast see my files on my
comptuter and i can run programs. I am unable to restore
or roll back my computers settings because the computer
says there are no previous system restore files.
Also when i look at my control pannel and select
add\delete programs there is no windows service pack
2,windows sp2 . But i have allot of ones that say hotfix.