Yesterday i was sorting my internal storage out on my Samsung Galaxy A3.When i tried to delete mp3 files it said failed to delete.So restarted my device it deleted the files but they came back.So in the end i did a full factory settings when my device started up the files was still there but they finally deleted.What caused this was it the sites at fault & should i be worried my device could've had Viruses? I always use Avast Anti Virus for my Samsung Galaxy A3 & my tablet.