Laptop Turns Itself On In Middle Of Night Then Freezes Till It Dies

I got my hard drive replaced a few weeks ago (dropped my laptop) and had an OEM version of Windows 7 installed. After getting home and re-installing all my drivers /programs, I used it like I normally do. Fast forward 2 weeks. I wake up and press the power button but the laptop is dead (this is odd because I usually put it in hibernate on a full charge before I go to bed). This continued to happen every day, my computer s dying overnight. Since last week I have been observing it overnight. Whether it be hibernate or sleep, my computer will turn itself on and become completely unresponsive (sounds like it's on but the screen is off. My test to see if it's frozen is to hit the 'num lock' key to see if it lights up). This event is a 100% occurrence. The only way to turn it off is to hold the power button for 5 seconds. Basically if I leave my laptop in sleep or hibernate, it will turn itself on at a random interval and immediately freeze. It will stay this way until it dies or I do a hard shut down. Also, if I leave it alone and go afk while working, it will go into sleep mode and freeze completely.