Sometimes spotlights are low voltage (12v) and are powered from a transformer - sometimes the transformer fails - you can often find the transformer hidden in the ceiling void - pull down the spotlight fitting and tug gently on the cable and the transformer will follow. DIY stores sell them. Add up the wattage of all the lamps and add a bit more to get the minimum wattage for the replacement txfmr.
If not low voltage then the lights may have lost mains power - check fuses/breakers first - then call an electrician.
Good luck... Take care...
Peccavi
March 2010
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