i15 Graphics card not loading 3D objects and slow boot. [SOLVED]

Hi there, 

I was avoiding this, but i need some help.

My family bought me a i15-3583-A30F, and im using for almost everything now, playing games, watching stuff and programing. It was working well at the start, especially the graphics card (Radeon 520, which it should run lots of games, but it can't, lags as hell, even properly configured and updated), but now, sometimes it looks like the VGA stops working, and it takes too long at a black screen to load the windows.

The VGA works for some time, but randomly stops loading anything 3D at all, games won't open and even Minecraft get's a error, openGL i think. When i restart the notebook, it comes back, but the problem persists.

I tried to do everything about the windows loading time, but had no success, and i couldn't find anything about the VGA.

Im highly dissapointed to dell notebooks, sorry.

EDIT: The problem suddenly stopped (Graphics card working properly).