I have a problem with my computer ( I'm using my daughters at present - only while she's at school ) in that there is no power.It was like that this morning so I checked everything and found the fuse gone in the plug.All other things OK, surge protector not tripped etc.So I changed the fuse, plugged in and there was a loud pop with a faint smell.I would suspect the power supply may have blown but I don't really know.So - any advice on what to do next, what and how to check?
The supply is a Switching Power KY-500 ATX P4 400W whatever all that means.Any help would be very greatfully received - thanks in advance.

Try cracking open the case and sniffing around to see where the smell comes from. You can also try a cheap PSU tester (they're about $10 online)

Also try unplugging all the devices inside the cabinet and switiching on again. If that works, the you will have to try pluging everything back in one by one. Leave the motherboard until last - thats the most expensive component. Check also that you do not have any "dangling" fan connections, such as on the CPU, which may be touching something.

I take it you didn't like the answers you got from forums.computing.co.uk.

Where exactly is this fuse that you keep blowing?

One of the suggestions at the other site was to disconnect the 20/24 pin connector and place a jumper between the green wire and any black wire and then turn on the PSU. I would also add that you should unplug the PSU before you attempt this. If the fuse blows again after this you will know that you need to replace the PSU.