help i think i have a trojan virus

the video that notice the start icon in the bottom left hand corner. it is not as it was before all this. did it maybe just delete vista and i need to re download it? then it will let me run normaly again. ok so i think as i was downloading a keygen i got a trojan virus. i do not know much about computers at all so you all are going to have to do me a solid and tell me what i need to do. When i fist startup my computer (if it was shutdown wrong before) the screen pops up and says somethin ...
![Modern Warfare 2 Keygen [100% Working/Legit]](http://img.youtube.com/vi/IDGqwXF4VO4/1.jpg)

















