worth fixing?

so i got my z71v back when they first came out. been a great little machine until yesterday when i tried to boot her. she just wouldn't start up. seems a common problem by reading the forums here. the notebook will power up, blue light turns on, hard drive light goes on for about 10 seconds, fan's turn on, then nothing else. the lcd screen remains off, usb ports are getting no power, pop in a windows cd, restart, nothing happens, it the power button in this state and it almost instantly turns off.

i'm going to guess its the mb or graphics like others are suggesting. before yesterday, when playing a game, i had gotten the blue screen of death about 3 times, windows would say a hardware failure or driver problem in the error box. about 3 times, the notebook froze, the screen changed to a red brick pattern. i would have to shut it down by the holding the power button as nothing else worked. this happened on tuesday night and it was yesterday that the notebook would not start.

now, i'm wondering if its even worth searching or attempting to replace the graphics for this machine. its not a new product so i'd think it might be difficult to find the part, but at the same time, would the cost of the part be worth it for a laptop thats what, 3yrs old?
i'm not even sure about finding a mb to replace it.