Windows Vista Game Lagging

I bought a game not to long ago (kane and lynch) and it does not run right it lags all through playing after i move my finger on the mouse pad 2-3 seconds latter the game will react.  i even tried lowering video quality and it helped but not to my satisfaction it still has a slow reaction time.  I have a dell inspiron 1420 with 2.5 gigs of ram and a nividia 128mb video card.  Can i ever solve this problem new hardware software settings ect...?