SandyDot-- It sounds to me like you have your discriminator ON and that is why you can't pick up the gold ring. This would prevent it from making sounds over certain denomination coins. Do you have a manual? If not, I recommend you find a way to get one. Pay attention to how the discriminator works for your unit.
To explain a little about what discrimination does, I'll explain how mine works:
1) I always hunt in ALL METAL MODE. The detector is the most sensitive at this setting,and should sound off over any metal target. When starting out at the beginning of each hunt, I turn up my sensitivity as much as possible. If I need to adjust it later, I will, but I almost never touch it. The loudness (or tone) of the noise depends on how close the target is to the coil when you pass over it (ie depth, off-center).
2) When I locate my target (ie find the spot where the noise is loudest; the target should be under the center of the coil when this happens) I switch through the range of discrimination until the signal is 'dead'. My particular detector has 6 different discrimination settings, numbered 1 through 6. At '1', the lowest setting, I get a clear audible tone, regardless of the metal type. At '2', if the target is iron, I shouldn't hear anything, unless it is a very large iron target, which will still beep at me. At '4', most foil and gold targets (these detect in the same range for my unit) drop out, but I will still hear sound for coins, brass, and other alloys. At '5', I won't hear a sound for nickels. If I am hunting a park with lots of bottlecaps, I -might- set my discriminator past this setting so I don't dig so much trash. The risk is I'm not digging nickels, so if there is a nice Buffalo nickel under me I'll pass right over it. As long as I am aware of the risk, I will make the decision based on circumstances. If my target still makes a sound when I am in setting number '6', I'll dig it, because this indicates to me that I have a good coin or piece of silver.
3) I usually make the decision to dig based on my tone and where the signal 'clips out' in the discrimination setting. This decision is based on practice with my detector, awareness of risk factors (like passing up nice nickels or gold rings) and familiarity with soil conditions (which can alter the responses of some metals).
If you start at the lowest setting and work your way up through the discrimination levels for each target before you dig it up, you will learn a lot. You will have to dig every signal until you are confident of what it is telling you. It will be tedious, but we all go through this learning phase.
