As it's a custom built desktop can you post the make/model of your motherboard?
What shows up on the monitor? Anything? Does it look like it's working but not getting a signal?
Everything is connected like it was when it was working? And you haven't changed any of the external switches (like the voltage switch you've already verified)?
No other LED's illuminate other than the single internal one on the motherboard?
I'm assuming the "O" and "I" mentioned below are the icons for the power switch:
and another one that has A , H , D i think or A , L , D but the switch for the first one is covering the 230 and 115 is showing . I have the O, I On I
but do you have any clue as to what the "A", "H", "D" are for? Or if it's really "A", "L", "D"?
Stating your case make/model number would be good, too...
It does sound as though it's been zapped and will likely require opening the case to go further, but please try to answer the above questions. This thread has close to 300 views, and the more details you provide the more likely you'll get more (or better) replies.