Mac Mini Wont Power On

I recently moved house, before which my mini was working flawlessly. After the move set up the machine and went to power on, and nothing.

After checking fuses etc. i tracked down a friend with a power supply and tried that. The machine power on and chimed, and so i assumed it was a power supply issue.

I got a new power supply today, plugged it in and the machine burst into life. It worked fine for an hour and a half while doing software updates etc. so several reboots and power cycles.

I then decided to move the machine into the other room after which exactly the same problem occurred. The machine will now not power on, no light, no chime etc.

It seems really odd that it worked fine for an hour or so on the new adaptor. Ive stripped the machine apart, cleaned everything, put it back together and still no luck with either power supply.

Has anyone got any ideas for fixing this machine, as my only other option is to strip it for parts, which seems such a shame for what was a great little computer, and could have been put to good use turning my parents into "Switchers".

Thanks in advance