Computer won't boot after adding second GPU

[hiiambang]

So, everything ran fine, and then I upgraded the power supply and added the second GTX. Now my system won't boot.
Since the PSU was new, I've checked to make sure all devices were powered and the cables were seated properly.
The computer powers on, no unusual noises, recognizes the GTX on the first screen, recognizes motherboard, processor, RAM, SLi-memory, hard drives, and disc drives.
The next screen, as if it was about to boot Windows, just sits there with the flashing underscore symbol in the upper left.
What am I doing wrong, or do I need to change something? Thanks.

Specs:
Asus M2N32-SLI Nvidia 590
AMD Athlon 64 X2 6000+ at 3.0mhz/core
4GB Patriot 4-4-4-12 DDR2 at 800mhz
2x XFX 8800 GTX in SLi
2x Seagate 500GB 7200.10 SATA (no raid)
Thermaltake Toughpower 850W PSU

 

[AlNom]

Did you plug in the auxiliary SLI power connector into the motherboard?

 

[hiiambang]

Did you plug in the auxiliary SLI power connector into the motherboard?

I never heard of that. What does it look like? The only cables coming from the PSU to the motherboard is the 24-pin and the 4-pin.

 

[Malo]

It looks like a standard molex connector like on IDE hard drives.

 

[hiiambang]

I can't seem to find what you're talking about. Here's my motherboard:

http://www.ixbt.com/mainboard/asus/m2n32-sli-deluxe/board.jpg

SLi is activated in the Bios.

I can boot with the Windows CD to get into setup.

Where do I go from here?

 

[AlNom]

Ah... your motherboard doesn't have one. Nevermind. I'm sure you meant it in your description above, but did you connect those 6-pin power cables (four in total) to both of your 8800GTX's ?

Do you mind taking a photo of the inside of your computer? (Just so I don't keep asking these questions).

 

[t0y]

My system is ancient compared to yours, but I would say he's referring to the white 4-pin socket next to the blue pci express slot. You should have a matching connector for that coming from the PSU.

edit: errr.. you should check it's really a power connector, my board doesn't have one of those..
edit: AlStrong replied first, listen to him instead, he knows better

 

[hiiambang]

Ah... your motherboard doesn't have one. Nevermind. I'm sure you meant it in your description above, but did you connect those 6-pin power cables (four in total) to both of your 8800GTX's ?

Do you mind taking a photo of the inside of your computer? (Just so I don't keep asking these questions).

Yep, all connected. 2x 6 pins into each, with the 4-pin and 24-pin going into the motherboard. I'll take pictures once my friend brings over a camera.

Minor "progress" I've made:

I went into the boot menu, and remembered that to fit the 2nd graphics card, I had to move SATA1 to SATA3, SATA 2 to SATA4, SATA 3 to SATA 5. I don't believe that makes a difference, but it is something that changed from when the setup was altered.

I enabled SLi-memory in the Bios, along with a setting that made CPUOCMAX right under it(it was enabled automatically after enabling the SLi-memory).

I can boot with the windows cd and get to the installation screen.

 

[Skrying]

So wait, was it booting up (turning on) before?

 

[AlNom]

I wonder if it's Windows 32-bit bitching about 4GB of system RAM + 1.5GB of GPU RAM....

hiiambang, Could you try booting up regularly with just 2GB of RAM installed?

 

[hiiambang]

I wonder if it's Windows 32-bit bitching about 4GB of system RAM + 1.5GB of GPU RAM....

hiiambang, Could you try booting up regularly with just 2GB of RAM installed?

It also hangs at the same place where it did before.

Yes, the system was running fine before on Windows XP SP2 with only a single GPU and older PSU.

 

[Skrying]

Remove your memory to the lowest possible combination you can get. But leave the two graphics card in.

 

[hiiambang]

Remove your memory to the lowest possible combination you can get. But leave the two graphics card in.

3 sticks were removed to leave 1GB, but still hangs in the same place.

 

[t0y]

I went into the boot menu, and remembered that to fit the 2nd graphics card, I had to move SATA1 to SATA3, SATA 2 to SATA4, SATA 3 to SATA 5. I don't believe that makes a difference, but it is something that changed from when the setup was altered.

You physically changed the connector to the hard disk that holds your system?
I believe windows expects the boot disk to be in a fixed controller port, doesn't it?

 

[hiiambang]

You physically changed the connector to the hard disk that holds your system?
I believe windows expects the boot disk to be in a fixed controller port, doesn't it?

I'm thinking it has to be something about that, since everything checks and then the system hangs right before windows.

There is an option to change the address for Serial Port1 in the Bios, but I'm not sure what it does. I'm guessing it has something to do with the SATA port on the back of my computer next to all the other ports.

 

[t0y]

Nope, that's another thing altogether, it refers to legacy serial or COM ports. The options are 2F8/3F8 right?

Can you try connecting the boot disk in its original SATA port with only one card to make sure?

 

[Davros]

just a thought swap the cards over