Even if the game freezes you should be able to CTRL+ALT+DEL yourself to a screen from where you can open task Manager and kill the process, but that's not the point.
Are you sure that the problem isn't hardware?
COD2 has 2 DirectX modes for rendering graphics, DX7 and DX9. Check these settings, it DX7 is enabled, change it to DX9. Unfortunately, for the time being, I cannot think of anything else to point out. The specs you included are fully capable of handling COD2 with high settings...