2001 Hyundai Tiburon. Didn't use it for 2 weeks. Went to start it. Nothing. 100% dead. Used my wife's car that night, then remembered the same thing happened last year when I left the car for a while, and later it started. Went back to the car when I got home and tried again. Nothing. Turned the key again... got a faint, faint light in the dashboard. Turned the key again and the light got a tiny bit brighter. Did a series of turning the key, resting for a few seconds and doing it again.... and all the power was back on. Car started, no problem. Wasn't like a weak battery or starter problem, it was like from completely dead not even any power to TRY to start the engine, to starting the engine with no problem. Car was fine till about a week later. If the car was running and I stopped and tried to restart it, it was completely dead. Dashboard clock and radio resetting itself dead. If I wait and keep trying to start, eventually power would come back. Last night after rehearsal I couldn't start it. No power at all, again, and turning the key wasn't helping. I got a friend to help with a boost. Hooked the cables up to my car while he was pulling his car up.... got back in my car (before he even opened his hood), and I had full power. Headlights, radio, everything.... car started. No problem. When I got home I turned it off and tried to start it again. Dead. Turned the key again and got a very faint glow on the dashboard oil light. Turned it again it got a little brighter. Tried to put the car in neutral for no good reason (fiddle with things) and when I hit the brake, the oil light went out. Tested this several times, and it kept happening. Also noticed that every time I turned the key and shut it again, about 2 seconds after I did I heard a quiet electronic like whirring sound coming from either the engine or the dashboard (my hearing is totally shot). Would last about 10 seconds and then stop. I plan to get it started today by fiddling with it, or AAA, and get it to my mechanic, but I'd like to have at least an idea of what the hell is going on first. Any thoughts? Ya'll figured my problem out last time. Thanks much, in advance.