1. Go to Tools->Options
2. Under General, choose "Audio settings"
3. Under Ringing:
a. If you want the PC speaker to ring, check "ring PC Speaker".
b. Ensure "Use selected speaker" is choosen, or choose the speaker of your choosing.
4. In the left pane, choose "Sounds"
5. Under "Select which events play a sound", ensure "ringtone" is checked
6. With ringtone selected, under Choose which sound to play select "Ringtone (Classic)". (You can change this back later, but some people had issues with the default ringtone, so this step is added in case you have that issue)
Please let me know if this solution works for your or not. If you'd like me to ring you with Skype for a test, let me know (I have Skype). If this does not fix the issue let me know. Thanks,