Hi gibsteroon and welcome to bleeping computer.
Did you use thermal compound when you installed the heat sink to the PCU, or did it come with a thermal pad?
Did you connect the square four pin PSU connector to the motherboard for the PCU?
One of the things that seems to be a given with most cases sold with a PSU, and that is that the PSUs are generally cheap, that could be a problem. If you have a voltmeter you could check out the voltage of the different rails. With the computer unplugged remove the 24 pin connector on the motherboard and place a wire jumper from the green wire socket to any black socket, this bypasses the motherboard's start up. You can now plug the computer back in and measure the voltage. You can find the color code and associated voltages at this
Edited by dc3, 21 July 2007 - 06:03 AM.