My xbox 360 keeps freezing?

So my Xbox is freezing and I have games only from only games on demand. I have been experiencing this problem today and 2-3 weeks back. My Xbox 360 hard drive is about 13GB and has only 5GB left since I downloaded a lot of stuff. It freezes so far in the game and online gaming. Cleared my system cache, and fixed up everything near the xbox and exactly organizing my area for playing video games enough for the xbox to breath and ventilate it's heat. Sadly when I begin to play, it freezes at the moment whenever I'm pulling up my scope to make my bullet rummage through a soldiers brain. I'm just only suggesting myself to stay away from the Xbox 360 for about 4-5 hours or even more so it can play and without any drawbacks. Yet sadly this is on my uncles xbox account he is paying for me. Is there anythin I could do? I fixed the disc tray which made no difference to me and yeah my xbox is in need of help I guess