I Have a Dyson 08 cylinder vacuum started to smell.(like a burning smell).Now it won't start any ideas?? It would be about 3yr old

Sounds like the motor has given up the ghost did you not get a 5 year warentee with the hoover?
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Look through there hints and tips, here in the uk they offer a excellent service package so if your in the uk I would contact them and ask what they suggest.