If you want the phone ring tone to go through the PC speakers and not a headset, this should fix you up.
To force the incoming phone call rings to go through the PC speakers instead of a headset, you need to go into the properties of the sound card of the computer and change the playback to the soundcard instead of the head set.
You can quickly access this setting by Right clicking on the speaker icon in the task tray by the clock, then Adjust Audio Properties or Playback Devices (depending on the version of Windows you are running), then select the Audio tab. Change the “Sound Playback” device to the SoundCard that is installed in your computer.
In the Voice tab, verify the “Voice Playback” and “Voice Recording” is set to the headset to insure all phone voice sound will go through the headset properly