Just built a new computer, turned it on and everything seems to work but theres no display

[Joshellis777]

I just built a new computer and everything seemed to be in order and when i turned it on all of the LEDs are on, even the one on the motherboard. All the fans are working too. But there are no beeps, the computer doesnt boot and nothing displays on the screen. I tried taking out the graphics card and connecting it with onboard graphics but still no luck. I read some advice telling me to change the switch at the back of the psu and i had a feeling that it was the problem so i tried it. However when i plugged the cord back in there was a load bang and smoke came from the PSU. Now its completely dead but i've ordered a new one. Anyway please could someone give me some advice on what to do when it gets here.
Thanks

 

[scout_03]

where you live if it is the 115 volts do not play with the psu switch you could have blow something else in the system also your motherboard could be defective she need to be test .

 

[Joshellis777]

I live in the UK, the voltage is 230v

 

[scout_03]

list all the parts you have with name and model even the old psu that blow out .

 

[Joshellis777]

list all the parts you have with name and model even the old psu that blow out .

Intel core i3 550
Asus P7H55-M motherboard
2x 4gb ram
500gb Seagate hard drive
AVP Galaxy III case
Asus Nvidia gt610 graphics card

The old psu was taken out of a dell inspiron 530 and it worked perfectly fine in there.

 

[shortstuff_mt]

Switching the voltage switch on the PSU could have damaged any number of components. What replacement PSU did you order? The importance of a high-quality PSU can't be stressed enough. I would review the troubleshooting checklist in the stickies at the top of the forum to make sure to avoid additional problems when the replacement PSU arrives. There's also a link to the checklist in my signature.