Is an Intel� Pentium� Dual Core T4200 (2.0GHz/800Mhz FSB/1MB cache) big enough processor to play the sims 3?

That processor is more than enough to play Sims3. However, the game is more graphics processor dependent. If your laptop uses the Intel 965 chipset w/ GMA X3100 integrated graphics, it will be SLOW for Sims3. Intel's GMA 4500HD would be a bit better but it is really the newer ATI and Nvidia integrated graphics that will run Sims3 decently.