I searched the web and I noticed that there's not so many good fixes for this particular problem with COD:BO so I'll take the time to write off what I've learned. I have Windows 7 64-bit and I had problem starting my COD:BO. Game got stucked at the "press any key" screen everytime I tried to play. So my problem was that my processor (Intel C2D E8400) utilized only 1 core. I think this is something to do with ACPI update from Microsoft (thanks ms, good job!). This is problem for both, Intel and AMD processor users. It all went away, when I updated my BIOS and checked that the ACPI setting was set to auto. (mobo: AsRock 1600Twins-P35) It was risky but definitely worth it. Some of you might just get your unutilized cores to work going to: cmd -> msconfig -> boot -> advanced opt. and set number of processor box unchecked and HAL option on. (I did not have that HAL option in my options, so I won't say a thing more about that) Some of you might just get it to work with Windows repair too, so if you're not willing to risk your BIOS I suggest you try repair your windows first.