The system has been restarting and I have tried replacing everything more or less.
The only thing I can think of is I have now used an Asus board which has a status monitor. It says the 12v channel is going up to 13v/14v. What does this mean?
I have a DVD and a CDRW drive, motherboard, ATI Radeon 9500, Firewire, Modem, 60GB HDD, 512MB RAM, Floppy, AMD XP 2400.
Could be a power issue, especially if it's spiking that much. I've seen a powersupply run at 12.5V a lot of the time with minimal problems, but being up around 13-14 sounds excessive. I don't suppose you have another around you can try a little swaptronics with?
If you just got the parts, you can likely exchange the psu for another. Just tell them it's bad, outputting excessive voltage causing system instability and you shouldn't have a problem.
What's the brand and rated wattage on the power supply?