iCheesy

Hello there. I had the exact same problem as you but I finally have mine solved and I hope it works for you too. Just like you, I also downloaded a free version of Videopad on my Windows 8.1 and as a result, my .rar, certain Office Word extensions, and worst of all my .mp3's were all affected with an unfamiliar icon. I searched high and low for a fix, but none worked except this guy's very simple How To (link: ) which solved this issue within MINUTES like a charm. So the credits all go to him. He has the steps in his video description as well, but just in case: 1. Start > Type "regedit" in search bar > Enter. 2. In your registry editor, go to: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts 3. From the dropdown menu, select the folder of the affected extension, in this case, the .mkv folder and expand it. There should be a folder named "User Choice" in it. Delete the folder. Don't worry, it's safe to delete however, your files' default program choice will get reset. 4. Do the same for any other affected extensions, example .mp3, .rar, etc. 5. Restart Computer. I hope this solution works for you as it did with mine.