Initially, I tried the guide in
http://support.apple.com/kb/TS1583 but it did not work because I do not have pending downloads.

I saw the guide below the article about msconfig.

I follow the guide in msconfig except I did not disable All services in:

http://support.apple.com/kb/HT1275

and added these web sites under IE's Internet Options-> Security -> Trusted sites

* itunes.apple.com
* ax.itunes.apple.com
* albert.apple.com
* gs.apple.com

and I got it working again after restart my laptop.