Hi, I recently got my hands on an old pc that I was told wouldn't boot up, blue screened on the windows xp loading screen. I figured it would be an easy fix, just reinstall windows and there we go.

Well once I got everything connected up the pc failed to boot up, nothing happened nadda. I figured this should be an issue with the PSU and so replaced it with an old one from a local trading shop.

Not knowing too much about hardware speccs but I figured a 230v would be ok to try.
I was wrong!
Upon turning it on the psu "flashed" / "exploded" tripping my homes circuit breakers, scaring the hell out of my partner and freaking me out! :D

The motherboard is a gigabyte GA-7VM400AM
The original PSU was a Macron MPT-350 (I think that's what the product is called)
the "new" PSU I tried was a ZECK 250w switching power supply MODEL no. ZKS-525A s/n:b 107886

Anyway i called it a day and left everything alone, but it has been sitting in my office taunting me ever since and before I rip it apart for components I thought maybe there is something that could be advised or done to get it up and running.

The power supply was obviously bad. Doing what you did to a dual voltage power supply, it should just not have turn on. That said, since it did short circuit, there's a question of did it damage anything inside the computer. With the side off, closely inspect for burnt or discolored wires and/or electric components The only real way to find out is to try another power supply. Preferably matching the power requirements of the original one, i.e. 350 watts.

The only availble psu's I have are installed in computers I use regulary. I've been asked to inquire if there is a chance experimenting with these psu's could damage them and so taking out one of our already functioning computers

No, not really. The only problem that I could foresee is when putting them back into the working computer, there's a possibility of jarring some connections loose and the computer not working properly. That can be remedied by just taking your time and double-checking all of the connectors to all of the devices are plugged in solidly

Thanks for the help, that resolved the issue. Got the pc working!