My 08 Chevy Aveo won't turn on at all!

I just bought a 2008 Chevy Aveo 2 months ago. When I replaced the O2 sensors the first month. Then 3 days ago I had to replace the battery because I always had to jump start it to get it going and later found out that I had a boat battery in it. Than last night I just replaced the headlight. Now... The car won't come on at all. No lights, electrical, etc. Nothing. Could any of the previous things be a factor? Or is it something different? Please help!