First, take a look at the Internal drive and the MicroCard drive and make sure you didn't load music or other files OUTSIDE of the Music folders.
Take out the MicroCard, do a full reset and see if it works. If it doesn't, remove all music files from the Internal, do a full reset and see if it turns on and stays on. If it does, put ONE music file that you are SURE is uncorrupted in it and see if it plays. If it does, start loading music files in small amounts and keep checking to see if it plays. If it suddenly stops working again, your corrupted file is likely to be in the last batch you loaded.
Or it's possible there is a problem with the device not related to corrupted files.