House Lights not working??

Can Someone please help!?
My dowstairs hall toilet and utilty room lights are working but the kitchen, dinning room and living room are not, No fittings or switches have been changed, but sometimes when you try to turn the broken lights on you get a flicker and then nothing for few hours! The fuse box is all checked and fine. Please Help!

checked all light fittings and switchs and all wirring is in the right place, i.e. no loose wires but as said 3 of the 6 lights downstairs work, fuse baox is downstairs too.