hi all got a problem with a kitchen light. started flickering about 2 months ago but worked ok till last week, when i tried to turn it on and nothing happened. requires 4no mr16 20w 12v bulbs so i bought and installed all just in case. my detector lights up on turning the switch on. but no light. my missus did purchase 50w bulbs and installed before i got home but the problem was there before she did this! any ideas??