Depends on how dead it is. I'm always trying to revive torrents, and I've had the best results reviving torrents that have only been dead for a month or so. The people who respond to reseed requests (bless them all, they are such dear hearts) have an easier time finding the content if it's recent. If it went dead five years ago, it's not going to happen. The site doesn't say when the last seed disappeared.
Hit the reseed request button, beg and plead in the comments section, and leave the torrent running 24/7. Get your friends to request reseed too, if enough requests come in, someone might notice (yes I requested reseed on this torrent, you're welcome.)
If you get some data within a few days, that's a good sign, means at least one of the current leachers was running when the last seed was up. If it stays at 0% for a month, it's dead dead dead. I've had a few pornolab torrents take several months to finish, and they looked completely dead for most of the time, but this has never happened to me with GTRU torrents.
PS If you manage to revive a torrent, it is your DUTY to seed it FOREVER. Someone was nice enough to find the content for you, now you need to make sure it's available for as long as you have an account here!