Finally built my first computer - bought a new case (had a stock PSU), new motherboard, CPU, heatsink/cooler, SATA HD, graphics card, and bigger wattage PSU. It ran fine for about a few weeks until last night. My USB printer attachment (bright blue LED) wasn't on, so I tried to power it up and nada. Checked the surge protector and it was powered, swapped out the power cord with no results, and then swapped out the 600 watt PSU for the stock 450. The smaller unit worked just fine, but on a whim I tried plugging the 600 back in - this time the 600 worked. Hooked everything back up, went online for a bit to make sure, and then shut the computer down and went to bed. This morning the same thing happened again, I did the same things I did last night, but the 600 still refuses to work. I looked through the other forum discussions for tips - I covered up the unused SLI plugs, literally moved all of the wires out of the case to make sure there wasn't a short, and still nada. The only thing I did notice was that there was a slight clicking noise when I plugged the 600 PSU in and flipped the switch to active. I haven't checked the PSU with my multimeter yet - I'm waiting to take a shower, wake up, etc... before I play with it. My big concern is that after I gave up on the 600, I hooked everything back up, closed the case, and hit the power switch. When I did that, the lights came on, went out for a second, and then came up/powered on like normal.
Having said all that, my three questions are : why would the 600 not power up until I switched it out and swapped it back, why did it ultimately refuse to start the next morning, and is the startup hesitation of my smaller PSU a sign of bad things to come?

Gigabyte 965-DS3 motherboard
Intel Core 2 Duo E6600
NVIDIA GeForce 7300 GS
Liteon DVD ROM
1 GB Corsair XMS2 DDR2 800

want to upgrade eventually to more ram (obviously) and get a GeForce 9750 GT

DOH - almost forgot -

Arctic Cooler Freezer 7
Xion 600 watt PSU (currently running case stock Xion 450)

I jus went through some trouble with a psu not wanting to start up and found that i had a dead cd drive. Intermitttantly it would not start after a shutdown and ended up finally giving up the ghost. To find it i started up the computer with everthing unplugged but the motherboard and started adding 1 thing at each reset until i would get to a roadblock or non functioning component.

Sorry, to say, but nope - it shouldn't be the problem. When I was swapping them out I checked them against the motherboard. I plugged each one in at the 24 connector and the little 4 (6?) connector. I kept the loose connecting ends away from the case, plugged each in, and flipped the switch on the back. The 600 would give a couple of faint clicks like it was trying to do something, but wouldn't power up itself or the lit USB cable end. The 450 would power up as well as light the cable. Beyond the cable (attached to a powered off printer) I had no drives or other components attached to the motherboard or the psu (with the exception of a NVIDIA 7300 GS PCIE graphics card).

Thanks

Try taking everything out of the case and just hook up the PSU, mobo, and HDD and see if it works. It sounds to me like the PSU crapped out and possible damaged the mobo or something in the process.

I can check that combo if you want me to make sure before RMAing the 600, but I don't think that there's anything wrong with the other components. I'm using the stock 450 right now with the same mobo, hdd, and dvdrw with no problems (except for an initial hiccup which happened the first time I switched from the 600 to the 450 - it hasn't happened since). I don't think it would be a conflict / power problem with the sata drive or my graphics card...

The thing is, even if you don't think it could be a problem, you should still evaluate it. Don't rule anything out until you've tested and are absolutely certain. I've hastily eliminated issues before, only to go back and find that was the problem.

I know it's a long process, but keep at it. You'll work it out.