2d collision detection

[kwanttitatti]

I'm making 2d game viewed from up and I'm having problems with collision detection. First I made array based collision detection and moving but I think it wasn't good. So I'm asking how I could make simple collision detection? I was thinking something like this: if(player inside of box) {player_loc - player_speed } where player_speed is how many pixels player will move everytime button is pressed but it didn't work as I wanted it to work. 

EDIT: I solved this already! Sorry for post!