No power

I have a 98 BMW 323is manual. This started about one month ago, when I would start the car I would hear a click sounding thing from the front of the car before the motor started. Now i've had it where when I would try to start the car I hear the click then everything would go dead. I mean everything no light no radio the whole car is dead. But if I wait for like 5 minutes and try it again I got power and the car would start. This has happened a couple times and everytime I would wait around 5 minutes and go again. But today I unlocked my car and everything died. I have asked a couple of buddies who said it might be the starter, a relay, fuses(i checked they look ok)bad ground somewhere. I checked the battery its good and clean. Any ideas?