Electrical issues?

I went to start my car. I had just previously driven it maybe an hour beforehand and when I went to start it, I had power and my dash cluster lights, headlamps, radio turned on, but after about 5 seconds it would just shut off all electrical out. if I try to turn it over as soon as I did I'd hear one click and no electric throughout the entire vehicle until I opened up a door then it would let me try to crank it over again with the same result I thought it was my starter which is a pain I got down to the starter and the positive going to the starter was pretty loose so I tighten that back up put everything back together and I'm still having the same problem when I turn it over I hear one click and then nothing no electrical or anything.