You don't call them dead coins yet, anything can change in matter of seconds in the industry, the fact they don't currently have any trading volume simply means there isn't enough attention towards that coin. In other words there isn't any buying interested in buying at the moment and this could be as a result of the project not been listed on a conducive exchange.
Majority of the time, exchanges contribute to the success of a project therefore if your project is listed on a shit exchange, it after the trading volumes of the project. Take that project to an exchange with enough volume and the project will recover that's why I said it shouldn't be classified as a dead project yet.