Okay. I am doing a computer setup in my car. Today I opened it up and got my wires I ran from the battery to test out the computer (I don't have a 12V DC source). To shorten the story, I had blown the inline 15A fuse I put in from the battery. It is possible that the negative and positive wires touched and it blew. But I don't think that is what happened. Is there any other way this fuse could've blown if it was ran to nothing (the wire with the fuse was just layed in place, with electical tape at the end to prevent this).

Did they touch and I didn't notice or what?

 

The quickest way to blow a fuse is to ground a positive wire.
That's where I would start looking.

 

You could have snagged the wire on something while you were running it through the car.

If you accidently stripped off enough insulation to expose the wire itself, it could have shorted against the frame of the car and blew the fuse.

Make sure your end is taped off and cant short. then replace the fuse and see if it blows again.