way over my head..help!

about two months ago my low coolant light came on but coolant and temp were ok so i figured it was just the sensor it ran fine so i didnt worry about it, then my door chime started to chime when i opened the drivers side door key in ignition or not, then the blinkers mysteriously stopped working all together, now my car wont start its acting as if the battery is dead, it wont even start or hold a charge being jumped off, the alternator is fairly new and the battery is less than a year old ...does anyone have any suggestions as to where to start first or what could be the problem...i susspect a short but i just know basic maintenance and troubleshooting and this one has me stumped please help..

1. Tighten the Battery cables.

1. Tighten the Battery cables.
its fixed it was a loose batter post