I am trying to make a diagnosis on my system through speaking to my wife, so I will do my best to explain my dilemma My system is home built and has a Thermaltake Silent Purepower W0014RU ATX 480W Power Supply. Over the past several weeks, my computer would perform some spontaneous reboots in the middle of playing games (low res, low stress kids games that my son likes) and having other random programs open. I noticed that Madden 2005 wasn't as smooth as it had been, and sometimes the computer just ran slow (I have run diskeeper on it and it's not fragged). I made sure the drivers were updated for BIOS, graphics card, etc. I made sure that the chip wasn't overheating. It would hit about 50 C max during high intensity games like HL2 and Doom 3, warm but certainly not in the category of overheating. I have fans up the ***** in it, including a PC card with two fans that sits below My ATI Radeon 9800 Pro. My rig sounds like a helicopter taking off. The Mobo is a P4C800 Deluxe from ASUS, and the CPU is a P4 2.8 GZ with the heatsink and thermal tape that came stock with it. I'm not doing any fancy overclocking or anything with it, but one day when the computer booted I got an 'overclocking failed!' message during POST although I never messed with the settings in BIOS. So, I think it could be several things, and need some advice on how to narrow down the suspects. How can I tell if it's the PSU vs. CPU vs. something else? A colleague of mine suggested that I take the PSU out of the system, plug it in and try turning it on. If it doesn't run, it's obviously the PSU and Newegg will get it back. Is there a chance that it would run by itself but not connected to the rig? If that does happen, does that mean that there's something wrong with the mobo or the cpu? Perhaps my wife will let me trash this one and I can build my new Athlon dream system. You guys kick *****.