Here's the story:
My brother has been borrowing my HHR for the last two weeks or so. He drove it around Calgary and then drove it out to Saskatoon for a week and drove back. He did not have any battery or starting problems.
I know my battery was getting weak because I had to jump start it around Christmas when it sat outside in very cold weather (negative farenheit temperatures) for a couple days without being started. Back in later Jan/early Feb the battery drained again sitting in the cold and I could not jump the vehicle. I had to pull the battery and charge it. It has held a charge since and did not have any problems with the cold weather since.
The last time he drove my car he mentioned the CD ejected and the clock on the radio reset upon start up. He left it parked outside my mom's place where I picked it up this morning. It started fine this morning but I noticed that the clock was reset and displayed 12:00 which I thought was odd.
I parked my car near my office and went to work and then went to the car show with my buddies. I arrived back at my car around 12 hours later. I pushed the unlock button on the remote and the lights came on and the doors unlocked. I put the key in the ignition, turned it and everything died. It did not even try to turn over, the radio did not come on, the dash lights didn't come on and neither did the headlights. I also couldn't turn the key to the off position only to the ACC position. I had to take off the underside cover and release the key from the ignition with a cylinder lock button.
I'm pretty sure that none of my interior or exterior lights were on to drain the battery during the day. Could my battery be completely discharged? Why would my battery completely discharge? Could this be a more serious issue with something electrical? Which fuses should I check first?
I am going back to my car tomorrow morning to see if I can boost it. I'm also going to check various fuses to see if that is the problem. This seems like a very odd situation.