i've fount out some things that may work for u guys, didnt tested it yet cuz i have a similar but not equal prob
look in control planel - services if "Kryptografiedienste" is activated
dunno name in english , should be something like "Kryptographie services"
install SP2 from microsoft.com
if u've installed sp2 beta like me u only got dx 9.0b , sp2 retail includes 9.0c
i've fount a program to deinstall direct x
check this side if things above doesnt work