Lighting, Light Fixtures, Ceiling and Exhaust Fans - Ceiling light blowout

I have a ceiling lamp with 4 bulbs, each 40W max. It is controlled by a dimmer switch. When I turned it on yesterday, I heard a crack but no light. One of the bulbs was found to have a fused filament with burn marks at the base where the metal and glass meet. The other bulbs are functional. The lamp would normally work with fewer than all bulbs. Now it doesn't work at all. I used one of those cheap neon lamp 2-wire tester-things and found that it "glowed" in all the 4 sockets in the fixture, regardless of the setting of the dimmer switch. But when I replaced the bulbs in the sockets, the bulbs did not glow. I then got a voltmeter, and measured the 2 leads from the dimmer switch. They always read 110V, regardless of the switch setting, but then they ARE connected to the home wiring. I am uncertain as to what may be happenning. Could there be an open/short in the ceiling box? Could the dimmer be bust? Do I need a new fixture?

Could anyone help me systematically troubleshoot this?

Thanks!

Dimmer switches sometimes burn out when a bulb does. Try temporarily replacing the dimmer with a regular single-pole snap switch. If the lights work well with that, then it's time for a new dimmer switch.