|I doubt it's your graphics card, I have the next one up in my laptop and games run smoothly.|
Have you tried rebooting? That's always my first suggestion. In a nutshell, the windows operating system doesn't completely retrieve RAM from programs after they are closed. So running high graphics game like those, can cause your computer to end up running poorly after a while.
Since this is happening with multiple games, I highly doubt it's the discs themselves. However it could be the disc reader. Grab a disc off your shelf (preferably not a high graphics game) and test it out. If this turns out to be the problem, take your laptop back get them to replace either the part or even the laptop itself you are persistently having problems.
That's really all I have to suggest, so, good luck.
Can I put a question here?