Had the exact same problem:
i8000 stopped ringing this morning. Phone still did the vibe thing at first, but after changing some setting (not vibe on/off) even stopped vibrating. Switching the ringtone resulted in a message "This will switch of silent mode" (I didn't set it to silent mode and all icons were indicating I didn't).
I read your solution, but decided try to switch USB from 'Storage card' to 'ActiveSync'.
This solved the problem, it's ringing again !
i just solved this problem... i had this problem too, it makes me cant sleep all night... try to move all your mp3 ringtones (that you transfer into it) to My Document folder, just make a new folder named ringtones in the My Document... then try and go to the settings to set back ur mp3 ringtone... hope it helps... cheers
U mean just move the all ringtones to a different folder then set the phone to tap that folder for ringtones? I have not tried this method of recovery. What I did was a bunch of random reset under different circumstances and ring type settings and it reverted back to original ring settings.
I sort of figured this has something to do with ringtones configuartions because I was badly hit by this problem twice...yeah loss tons of sleep and hair over it. I believe the problem lies with me configurating my ringtones to a folder in My Storage. When connecting my computer to the phone and setting USB connection folder to My Storage. I believe that if I did not set back to Activesync at the end of the session, WM will not be able to access the ringtones and screw up the ring config. So it's best to keep your ringtones in the root windows folder since u can't access this folder other than using Activesync.