Question Very strange speaker problem!

I need help!

My father has been using his HTC Desire for quite some time.

Recently when he receives incoming calls, the ringtone cannot be heard at all. the vibration also suddenly stopped working.

This points to a speaker problem but the strange thing is, when the phone is rebooted, the speaker actually outputs the HTC startup sound and i can hear it.

Also, when i play music, i can hear the music but it is very soft (even at max volume). It was not like this before.

I have checked all settings, the phone's incoming call tone is set to maximum and is not silent.

Is there any method, way, app, software i can use to test the speaker? Is it a corruption problem or an app issue?

I have tried rebooting the phone but to no avail. Thanks!