If you have a computer with the Silverlight 2 developer bits installed you might see the following message when installing Silverlight 3.
Unable to install Silverlight. Your Silverlight developer components are out of date.
more here
If you have a computer with the Silverlight 2 developer bits installed you might see the following message when installing Silverlight 3.
Unable to install Silverlight. Your Silverlight developer components are out of date.
more here