Would not start for two days?

My car, wouldn't start 2 mornings ago. It wouldn't take a boost, jump pack, a warm charged up battery, nothing. It wouldn't even make that click you hear. Just nothing. But I still had power to everything. Headlights, gauges, blower motor, interior lights. Then yesterday at 9:30am in -20 C, while waiting for a ride, I tried in and it started. I drove it 650km, came home, turned it off, and when I tried it again last night at 11:00pm, it was dead again! I can't have this happening to me, winter is just starting and it hasn't even been that cold. This car is just a never-ending fixit pit! What could be the problem?