Microsoft is updating Silverlight, but it won't install on an AMD system. I don't know about Intel.
But on an AMD system it gives the error that you can't install on a PPC computer

there is an easy for for this

step 1:Right click on the package
Step 2:Show Contents
Step 3:Navigate to Contents/Resources/InstallationCheck
Step 4: Delete InstallationCheck
Step 5: install pkg