I recall this problem having something to do with Java...
What version of Java are you using ??
Try uninstalling your Java from the add/remove programs and then re-install the JRE 5.11 offline version....
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11
I think it your WMP has something to do with version 11 and a bug, I'm not to sure...
Try itunes it's heaps better..
