OK, It happened to me again today! I was tweaking the phone a bit yesterday and before I went to bed, media player and ringtones still worked. This morning when my G-Alarm went off it did not make any sound. I knew immediately what had happened. It seems like the combination of Coreplayer + G-Alarm causes the bug.
This time, I had used Sprite backup to save all of my "system settings" which includes all of the files on the main phone memory as well as many registry keys (~150mb). I saved a Sprite backup both before AND after the ringtone bug happened.
--Restoring the older Sprite backup did NOTHING. Media player still would not start and the mp3 and wma ringtones still would not play.
--After a hard-reset, I restored the Sprite backup from AFTER the bug happened. This did not cause the bug again. So whatever is causing it is not a file on the Main memory of the phone and it is not in any of the registry keys that Sprite backs up. Interesting...
I think my next step will be to save the entire registry in a text format (.reg) from before and after the bug and compare them to find out what has changed. It MUST be in there somewhere....
But for now, I am happy with all of my apps and data restored with minimal effort. Instead of Coreplayer, I am using good old
TCPMP which seems to be working great so far..