Too many wires in box for exterior floodlight

[rpotter]

I'm hoping to replace an older exterior floodlight. I took the old fixture off, and found a tangle of wires in the box which puzzles me.The overall situation of the box is this: There is a light switch inside the house just behind the box. Outside the house there is a GFI outlet and a conduit going from it up to the box. The switch controls both the GFI outlet and the floodlight. Coming out of the conduit I have two white wires and a blue; coming out from the house wall I have a white, black, and bare (grounding) wire. The white from inside the house seems to have been coupled with one of the whites from the conduit. (see attached photo). The black wire is the only hot wire.I have a new floodlight socket ready to go -- but of course it has just one black, one white, and one grounding wire. How the heck to I connect it?

[HayZee518]

box

remove the gfci from the box and take a look what wires go where. one of the stranded white wires may go to the green grounding screw. this will go under the green screw in the round box along with the solid bare wire. the other white stranded wire goes to the line white on the gfci. the blue goes to the line screw on the gfci. in the round box, the white and blue goes to the solid white and black which I'm assuming comes off the switch inside. your fixture [new] will connect to the black-blue and white-standed white. the bare goes to the other bare and white which is connected to the green grounding screw.