boot problem: sonata & A7N8X Deluxe

[subgenius]

I'm building a brand-new computer for the first time using the Asus A7N8X Deluxe, Antec Sonota case and the included Truepower 380W power supply. After installing all the hardware, I tried to boot up for the first time, but after about 5 seconds, the computer powers off and nothing ever registers on the monitor. The green motherboard light is on, and the red light near the AGP slot is off. All three fans (CPU, PSU, and case) seem to work fine. No strange sounds or smells.

Here's what I have in the case:
Asus A7N8X Deluxe
AMD Barton 2500+ w/ included heatsink & fan
Matrox G550 video card
2 x 512MB Crucial PC2700 Non-parity RAM (in sockets 2&3 on MB)
Lite-On CD-RW Drive (Master Secondary)
Maxtor 160GB Ultra ATA HD (Master Primary)

*I don't have a floppy drive, and I was hoping it wouldn't be necessary to have one.

I plan on installing WinXP Pro, but haven't been able to get the system going, so I can't even put the install CD in the drive yet.

I've posted this question before and some people mentioned the 4-pin auxillary power supply, but I don't see where I could plug this in on the MB.

Also, the case fan is plugged into the power supply, but not the motherboard. If I'm supposed to plug the case fan onto the MB in addition to the connection with the power supply, is there a connector on the fan, and if so, where?

I'm guessing the problem has something to do with either the CPU, power supply, heatsink or the fans since the MB has an overheating protection feature that shuts it down before it can overheat, but if that's the case, I'm at a loss since everything that I can see appears to be working fine. I'm really looking forward to getting this thing up and running, but so far it's been nothing but frustration. Any help or list of possible problems anyone can provide would be much appreciated. Thanks in advance.

 

[sygyzy]

Is your CPU fan plugged into the correct CPU fan header?

 

[subgenius]

Unless the person who wrote the manual was trying to pull a fast one on me, I think I've got it in the right place.

 

[KentuckyFisherman]

I'm in the final stages of building a box very similar to yours, Subgenius and I also am having boot problems, although of a different nature.

First, I've learned our board doesn't use that square, 4-pin auxiliary power connection, so that's not the problem.

Start the system and look closely to see if the CPU fan starts and seems to spin pretty fast. Our board/BIOS does have an automatic CPU temp shutdown system, so if the chip gets too hot or the heatsink fan isn't spinning fast enough, the BIOS will shut her down. You might also check the pins on the fan to see that you have it plugged not only on the right pins, but that you have the orientation correct. If you have that plug reversed, it might spin the fan but not cool properly or report the RPMs properly or something.

The other possibility is that you didn't mate the heatsink to the CPU correctly. Could you elaborate on whether you used the stock heat transfer material, whether you peeled off the plastic covering, etc? It's entirely possible to have a heatsink and fan that appear to be mounted correctly but still aren't cooling the chip because of some mistake in the way the heatsink was mounted.

I'm nearly convinced it's a CPU heating problem, or at least that's what your BIOS thinks.

 

[Opie001]

I have a Sonata, a Asus P4P800 Deluxe and Radeon 9700 (np). My motherboard doesn't always recognize my AGP card on boot-up, until I press reset. I don't know if this is a card problem or power problem. Any thoughts?