When you did a clean install, did you reinstall all of the necessary system drivers before installing silverlight? ASRock > Products > Motherboard > H55M > Download
If you have not, completely uninstall silverlight (or maybe even better yet, do a system restore to before you installed it), reboot, then download and install all of those drivers, except the INF driver. That one is pretty out of date. Instead, go straight to Intel and download the INF update utility here and run it: http://downloadcenter.intel.com/Deta...ility&lang=eng
Reboot again, run Windows Updates and see if there are any recommended updates for your drivers. If so, copy/paste that screenshot to here so we can see which ones we'd recommend further updating at that point.