You'll need to define your system- e.g. motherboard, CPU speed, RAM, video card & driver, Linux distro, etc. Telling us exactly what you're running will assist us in helping to solve your problem.
Also, in the future, please give your thread a definitive title, like "Problem installing Call of Duty 4". Ones labeled "Urgent" or "Help" get overlooked by many that could assist you, as it is requested before you post your problem not to use such vague thread titles.