some games are very heavy for notebook graphics, so first of all make sure you are using latests nvidia optimus drivers, second, if the game is lagging, go lowering the graphics up to a level where you can play it at acceptable framerates.
Some games may be lagged even at very low graphics, so you can lower the resolution or search online for performance fixes (lowering graphics in the game config file and other)
if you are saying that the game is running at good frames but the controls response is very slow, try removing vertical sync before lowering graphics.
It sounds like you may be inadvertantly running off of the Intel HD graphics instead of your dedicated card if you do indeed have all of your drivers installed correctly after the reinstall of W7 you mentioned above.
Under your power options make sure you have selected High Performance and not Power Saving or some other setting that would switch you to integrated.