Can this computer run Mafia II Intel core 2 duo 2.66 GHz winXP 2GB ram 50GB HDD free

Your CPU, RAM and free hard disk space are fine as mafia 2's min requirements are:
CPU - Pentium D 3GHz / AMD Athlon X2 3600+ or better
RAM - 1.5GB
OS - Windows XP/Vista/7
HDD - 8GB Free hard disk space
GPU - Geforce 8600 (or equivalent) graphics card with 512MB video memory

Make sure your graphics card meets the requirements as well. Meeting the
minimum specification should allow you to playthe game in medium settings
at a resolution of 1024x768.