Did you check for voltage at the holder before sticking the bulb back in?
When I do electrical problem solving on buildings I find my first 'working' point and then work my way along towards the non working item and the problem 98% of the time presents it self. Now that first working point might be the load side of the fuse, but at least you know you've got power, and fuse is good. Checking power is getting to the item is the 2nd thing to check, if there is, then it's a ground issue or lamp. Check grounding and then test the lamp with a continuity meter or in a holder you know works. If that all tests fine and there IS power at the holder I'm out. If there is no power then work your way back towards the fuse checking and testing connectors for power.
Also sometimes there might be two issues, say a short that has blown a lamp but not a fuse for example. So it's not as simple as just checking one thing.
Good luck
Felix