Overclocking a laptop CPU beyond any factory setting or allowance in a utility (some gaming laptops have a function that allows overclocking to a degree) is generally not possible. Not only that but even if possible is not recommended due to the inherent poor cooling capability of a laptop's cooler design for space limitations.
I would wipe out the Nvidia drivers with a software removal tool like CCleaner and download and install them from Nvidia's website. It could be the factory put some crap in there that's conflicting with the video card drivers. But before you do all that, try running the games at lower quality settings and see if the problem persists.