I just bought a used 1984 944 5spd. Everything was running fine until one day I shut the car off in the driveway and now when I try to start it it just gives a loud click and everything powers down. If I let it sit for awhile then put the key in the ignition and turn it it to accessories I have power to everything but as soon as I try to start it theres the loud click and everything powers down again. Any suggestions

have you checked the starter? and your battery connections? sometimes loose connections will still give power for accessories, but click and have nothing when you try to start.

Check the state of charge in your battery by hooking it up to a charger. If low, charge about an hour at 8-10 amps. If the battery is old it won't hold the charge for long. As Dean said above, check your connections, especially the ground connections, particularly the one on the firewall up top near the battery itself. Use copper never-seize on the ground connections if they are in bad shape. Good Luck