Along Vasco's suspicions...RTFM first. Get that manual and make sure it isn't something terribly simple just set wrong. But I'd also emphasize, DO NOT PRESS TRANSMIT unless you know there is a working antenna on the radio. While most modern radios will protect themselves, some can easily burn out if you transmit without a working antenna connected to them. So if in doubt--keep it to one quick click, or don't transmit at all.
In a pinch, you should be able to take a wire coat hangar, a two foot long alligator clip (jumper wire), or other piece of wire and press it into the center hole of the antenna socket, and if the radio is working at all, it WILL receive something from strong local signals. If it still receives nothing, makes no noise
The radio is set up wrong, or broken.
It can be something as simple as the internal connection to the internal speaker breaking loose. Or the transmit switch in the microphone being stuck. Or, the power lead to the radio may be corroded, chafed down to one strand, or a bad fuse. Sometimes there's one fuse in the power cord and another at the breaker panel "oops" so it helps to check the power cord, make sure the radio is getting proper voltage with enough power to at least light a test light or small cabin
When all else fails...some marine electronics
shops will still "take a look" for free.
Incidentally, for under $20 you should be able to get a "VHF emergency
antenna" that comes in a plastic tube. Maybe a dozen feet of cable and a short antenna you can stick on the rail, etc. Makes a good way to test that your radio/antenna is good, even if you never use it for anything else.