I successfully downloaded 2 games. 1 says that there is no Direct3D. The other says there's no initgraph. help?

on another computer i downloaded and successfully played the same 2 games. on this computer the 2 games were successfully downloaded as well but I'm not able to play them because of errors with the computer. another yahoo! answers user had a similar problem and in the answer some one recommended going to DXDIAG, clicking DISPLAY, and checking to see if the Direct3D Acceleration was Enabled. i did that and it says that the DirectDraw Acceleration, Direct3D Acceleration, and AGP Texture Acceleration are all Not Available. For the other game, when i try to launch it, a small window comes up and says, "Startup engine [Graph] failed. -> Init graph device failed." I don't even know what that means, but on my other computer, that never came up. can anyone help me???