Hello people

Ok i have build a computer for a friend (i know how to build a pc but i am no guru), all the parts are new and compatible, only the hdd and dvd drive are from his old pc. Here is where my problem starts. After conecting everything up my friend (no knowledge at all) changed the voltage switch on the back of the psu to 115 from 230 and fried the psu before i even got to switch it on. We then changed the psu for a new one again and then it still didnt work, so we then took back the mboard cpu memory and changed all that. I have put it all back together and it still doesnt work. Here are my questions: 1) if the psu fried the cpu, mboard, and memory could it have done the same to the hdd, dvdrom, and would it affect the cables from the exterior case that you plug into panel 1. 2) if the hdd and dvd drive were fried then would this prevent the computer from starting up. and finally 3) can you connect a hdd and a dvd drive to the same IDE cable (i have the hdd as master and the dvd drive as slave) and would this affect the pc from starting up.

Spec: 1 gb ddr2 800mhz, amd athlon 64 x2 4000+, ECS 6100SM-M micro atx

Hope this makes sense and i thank all who take the time to help.