Have owned the HTC EVO 4G for about 18 months with NO prior problems. The issue for me was a sudden loss of headphone volume control and my Vlingo InCar app would spontaneously start.
What didn't work:
cleaned charging port w/toothbrush
toggled bluetooth settings (don't use bluetooth)
Restart
HTC update
PRL update
What did work:
Uninstalling Vlingo
-Peace Out
What didn't work:
cleaned charging port w/toothbrush
toggled bluetooth settings (don't use bluetooth)
Restart
HTC update
PRL update
What did work:
Uninstalling Vlingo
-Peace Out