I am looking to buy a Windows 7 Dell Inspiron 660 with 3rd gen i5, 8gb ram, 1tb drive, 300w power supply and on board graphics. This is fine for most things my family will be doing, but my son would like to play Minecraft and Call of Duty World at War. Call of Duty is an older game, so will the on board graphics work? If not, can the inspiron 660 be upgraded? Does it have an extra slot for a video card? I'm new to all this and not afraid to learn and put in a card. The sales lady suggested a radeon 6670. I looked at the power supply requirements though and it says 400w. I do not want to spend all this money and fry anything. I do NOT want to upgrade the power supply. I only need something good enough to run the games decent. They are not big PC gamers...mostly on game systems. Thanks for your suggestions.