No sound incoming phonecall only buzz

[Guest]

Hello to all,

I installed android on my HTC HD2. Everthing is working fine except when I receive a phonecall there is no sound, only buzz.

I tried all setting, selected a ringtone etc. but no result. There is a sound when I receive a message so thats working fine.

Do you know how to get back my ringtone.

Thankx