I've just re-cased my computer. I got the new case free and thought I'd be able to swap everything over myself but apparently I've done something wrong. I'm OK with components generally but wasn't totally confident about doing this.

So, my question is, when setting up a new PC or moving old components into a new case, what could I have done which causes the power cable plug to short/fuse when I plug it in?.

Is this likely to be an issue with the cables from my PSU, or could it be the internal case connectors?

What steps would you take to diagnose the problem? I'd rather not start again if I don't have to...!

Thanks in advance,