Hello there, I really hope someone can shed some light on a problem I have.
I thought I would upgrade my power supply as I am running quite a lot of stuff off a 300w supply.
Last night I installed a totally new 580w supply and switched the PC on. Absolutely nothing, I seem to recall the a pc power light flashing for a second then nothing. Ok I thought, DOA supply unit, I tried it in my brothers PC and nothing there either.
What is really upsetting is, the 300w supply is now not powering up either machine. Just to check, I took the 300w to work and put it in one of the computers there - it powers up.
Have I killed both PC's? I now read that American PSUs should be 115v & Europe (where I am) should be 230v. The 580w supply came switched to 115v. Has that done something serious?
I would really appreciate any suggestions

Yup, the PSU is fried. I am surprised you didnt hear a pop. The switch configures the main transformer (the part that adjusts line voltage from the wall into a voltage and current that the circuits can handle.) When you have it on 230, everything will be find, but on 115, it will send too much current to the circuits.

thank you for your reply.
However, the computer does not respond with a working PSU now, is the motherboard dead - if so can it be revived at all?

Its quite possible that a spike left the PSU into the MB at the same time the PSU died (not all PSUs will give their life to save the MB) There is not an easy way to recover a motherboard. It will require someone who can get down to the component level and find the chip(s) that are dead and replace them. That service is not cheap...not as cheap as a new MB. I would make sure that the Processor is still good as well.