It helps everyone if you provide as much info as possible when posting a thread. Hence all my questions. If Avast Free was blocking it you would have seen a pop up message. Open Avast and go to the Maintenance tab then click on scan logs and virus chest. If PowerDVD is not listed in there then Avast has nothing to do with it. Keep in mind there was just several Windows Updates also. What version of Windows are you using? There are plenty of free DVD programs also Have you checked the Cyberlink website to be sure your using the latest version? Keep in mind that Avast does not silently remove or detect anything. You get a pop up in the right bottom corner if it was detected as malicious. If the behavior blocker detected it then you would have received a pop up but in the middle of your desktop. Also in the right bottom corner. If none of those things happened then it is clearly not an Avast issue.

http://forum.cyberlink.com/forum/posts/list/28321.page