How would one say "my computer died"?
If it hangs (not responding to any input), you could say 


  我的电脑死机了。


If the screen blacks out, you could say


  我的电脑黑屏了。


If it doesn't turn on, you could say


  我的电脑不亮了。 


or


  我的电脑打不开了。


If it is completely broken and needs major repair, you could say


  我的电脑坏了。 


or


  我的电脑完蛋了。


Note: All above are used in Mainland China. I know they're expressed differently in other Chinese-speaking regions (e.g. Taiwan) but I don't know what they should become.