Before I begin, I'll say this: I'm about 85% certain that the problem is a short in the CPU socket - so I RMAd the motherboard, and they sent it back unrepaired. So before I call them and chew them out, I want to make sure there's no other possibilities. I put the CPU (Athlon XP 2600 w/ 333 MHz bus), RAM (PC2700 DDR), and video card (ATi Radeon 9800 Pro) in, so I could boot up it up and see the BIOS and make sure it ran. Well, it didn't. It stayed on for maybe three seconds, then shut off, not even enough time to display anything. However, the power light on the mobo (not on the case) was on. So I ran the necessary tests, and it came down to the CPU: no matter what other hardware was installed, it never works with the CPU in place, and always works without the CPU. So I called Asus, and they assured me it was a CPU problem, so I RMAd the Athlon XP. I got the new CPU, and the problem persisted. So I RMAd the mobo, and it was returned with assurances that it was in perfect working condition. But the problem persists. The test result sheet they gave told me to check the add-on cards, RAM, CPU, etc., all of which I have done, and all of which are in perfect working condition. So it again comes down to the motherboard. I am, of course, open to the possibility that it's a power supply problem (MT-400, 400W, 12V, meets all of the mobo's power specs, got mostly good reviews). But if it is a power supply problem, why does the system work when I take the CPU out? This has GOT to be the fault of the CPU socket in the mobo, but they won't replace it for me! Thanks for any help.