I dunno why but my game crashes right after I run the game..it shows a SHORT very short sequence of the activision or I dunno sign and then boom...it freezes..black screen of death! How can I fix it? =(
I ran into the same situation, but not for MW2. Although I am no expert or something, but I just want to tell you about what I have known about this so far.
1) There might be some problems with conflicting process against steam client running during the gameplay, steam has a list of that on their website, google it.
2) Watch out for iTunes related process, those consume lot of memory, which may lead to crash and even total death of computer.
3) Video card drivers, keep those update, and check whether your DX is up to date.
4) Check your hardrive.
5) If all those things are checked and the game still crashes like hell (Especially total death of computer continues to happen), then you probably need to do something about BIOS settings. This happens to me overtime for some reason, maybe because my processor and motherbroad are AMD exclusive, I ran into this when I was playing Fallout3, GTA4, Crisis, Company of Heroes (the list goes on and on...)
This is highly unrecommended for most people as changing settings of BIOS may lead to failure of booting and exiting Windows, you probably need to google it somewhere, cuz this is not a usual problem.
Hope those help
Cheers