How to fix a computer that has blue screen problem?

How to fix a computer that has blue screen problem? Last night I installed a game to my computer and then I get up and the blue screen of death thing comes up. I tried going into safe mode and all of that and it won't even let me do that. It says that "windows installed a new hardware or software" etc.
I do not have windows XP disc. What does anyone recommend I do to solve this problem. Can anyone help me to solve this problem? Because its freaking me out and really don't know what to do anymore.
