"please wait while windows configures itunes"

Problem
If you get this message after upgrading or installing itunes:

"please wait while windows configures itunes"

Followed by a reboot message that never fixes it self after a reboot.

Solution
From : http://discussions.apple.com/thread.jspa?messageID=5440570

go to start menu --> run
type regedit, press enter
go to computer/hkey_classes_root/
find pcast and right click it
click permissions
during the course of this you may get a message saying you cant change anything, but you can change who can change things. click ok on it.
click advanced, then owner tab
change the owner from administrator to whatever name you are using
click ok twice to get out of the pop-ups completely
right click pcast again
click permissions
click OWNER RIGHTS
by full control and read click the allow boxes.
click ok
all set!