Ceiling light with dimmer, not working but still 'buzzing!?

I have a ceiling light which has about ten small 10w halogen bulbs. It has a dimmer switch. It suddenly stopped working, but I can still hear the 'buzzing' sound that you get with dimmer switches when I try to switch it on. Could it be that one bulb has gone and the whole set won't work? (have new bulbs now so will test at weekend), or could the switch fitting be broken. Any clues?! Many thanks. Just don't understand why it's still buzzing, but not working.