You can try to sign up again with the same ID but there will be a waiting period before that ID can be used again. (the length of time varies among providers) Yahoo is one year. Of course you won't have access to any emails you had in the account originally.
In the future, make sure you log into your accounts periodically so this doesn't happen again. (as you learned the hard way) Set a reminder and log in every couple of weeks. Good luck!