My games keep freezing

I bought a game new. It kept freezing, so I took it back for another copy but that one didn't work either.

So I took the second copy of the game back again and they finally gave me my money back. I bought another game (Sniper Elite 3) and I also bought a one year warranty. After it finished installing, I opened the game for the first time and it said loading data. It sat on a loading screen for about an hour. It didn't freeze - it was just loading.

What's causing two different games to freeze? How do I fix it?