My computer downloaded 3 updates this morning. The first installed successfully (acer corporation - display - x223w), the second is a security update which is the one that is hanging at 25% (security update for microsoft xml core services 4.0 service pack 2). I cant even stop the installation. It asks for permission to continue, I allow, the stop installation button changes and looks as though it will stop and then it just starts up again?? Its been at 25% for about 6 hrs now. Any suggestions?