Whatever the problem, you need strategies to tough it out. Grab their attention - do something bizarre so they can't help but look, listen and learn. Eat from a (rigged) can of dog food, present them with a CSI-style scenario, discover what they're into outside of school and base lessons around that. Turn those tricky abstract concepts into concrete examples.
Accept that getting their complete, silent attention will be tricky. Tread lightly with whole-class teaching. Instead, put the onus on them to direct their own learning. Set projects, visit the library for research, spend time in the technology suite. Make your life bearable while still trying to reach those who want to be taught. Devote your time to understanding and helping each individual.
You might not be able to exorcise the demons completely, but if you can survive the class from hell, nothing need ever scare you again.
Sue Cowley is an author, trainer and presenter. Her books include Guerilla Guide to Teaching (Continuum). www.suecowley.co.uk.