My cell phone, model SGH-U600, does not ring. It does not ring for incoming calls (while screen is flashing), for incoming messages (screen display ok), and when I make calls, I cannot hear the dial tone nor the person answering the call... Everything else works fine! Is it possible to solve this problem?

If it doesn't ring when there's incoming call even if the phone is not in silent/airplane mode, then the problem is with the Speaker, but if you can't even hear the dial tone and the other person speaking/answering, then there's another possibility. Your phone must have two speakers, one as a ringer and the other as ear-piece-speaker. The one you hear ringing and or when playing songs is the Ringer and the other you hear through when answering a call or the keypad sound is the ear-speaker. I would suggest you to check with a headset so as to find out whether there's internal circuit problem. If you can hear through the Headset, then replacing the speakers will fix your issue, but if you don't even hear from the headset, then the problem would be complicated and the repair will be more difficult.
With both issues, you'll need to visit a Samsung Care or a local Mobile repair shop to get it fixed. They will charge you for the replacement and for the service. But before that, you'd need to confirm what's the cause and if it's going to complicated and you are likely to spend much for the repair, I won't recommend getting it repaired. If cost of repairing is more or less than purchasing a new handset, then I hope you also won't opt for that.
Let me know if you need further help. But first try with the Headset.
Good Luck.
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