I need help troubleshooting this problem with building a PC?

So, I thought I would upgrade my PC. I went out to buy a new motherboard, processor, and ram. And in doing so, I was left over with enough components from previous upgrades as well to build another computer and sell it. In effect, earning back majority of the money I just spent in the upgrade I did.

The problem is not with the upgrade process, it’s with the computer I’m building to sell.

I took the older motherboard, processor, and ram and transplanted them into a brand new Antec case. I didn’t unmount the processor from the board, and I left the memory in the dimms. I moved over the hard drives as well, kept the OS in place (vista business). I installed a brand new power supply unit as well. I had a reasonably new graphics card that I was using, and put that in the PC. I make all the necessary connections, all the connections seem nice and snug.

I boot up the computer, and it goes into windows just fine, and it had to download new drivers for video, which it did with no problems. But I’ve now noticed a series of weird issues and a series of reboots with no blue screens of death.

-If I eject the optical drive by hitting the button on the drive, it reboots.
-If I make a new connection in the back of the computer, usb, 3.55mm cable, anything, it reboots.
-If I try and put in an OS disc to reload a new OS, it will continue to reboot over and over each time it engages the optical drive.

I’m not sure what to make of this problem, never seen it before. My guess would be a short somewhere, but I’m not sure. I was going to just take it all apart again, dust it all out again, and reconnect everything to just be sure.

I don’t think it’s the Power Supply, as it’s brand new. The optical drive is brand new too. And the case is brand new.

Any help?