I am placing a ceiling light. The light fixture that I purchase has two wires, 1 white / 1 black / 1 ground. In the ceiling I have a total of four wires... 2 white wires and 2 black wires and 2 ground wires. So I hook the two white wires to the white wire in the light fixture, and two black wires to the black wire in the light fixture. I hook the ground wires together. I then turn the power on and when I turn the switch on it blows a fuse. What am I doing wrong.. Need your help... thanks

Most probable wiring situation here is;

One cable (a cable is two or more wires in an outer covering) brings power to ceiling box. The black is hot and the white is neutral.

The other cable goes to the switch. One wire, usually white, is used to take power to the switch and the other, usually black, brings power back from switch, when switch is on.

The correct connections would be the white of the light fixture to the white or neutral of the cable bring power to the ceiling box, the black of that cable to the white of the cable going to the switch, the black of the switch cable to the black of the light fixture.

Your task is to determine which cable brings power to the ceiling box and which cable goes to the switch.

Do you have a meter or test light? Does either of the white wires have a piece of black tape on it?

Harold:
This worked like a champ! Purchasing a test light and reading through your instructions made this task "a done deal". Many thanks. Certainly appreciate your time and help.
On to the next task... ;-)