Building JABOP but it won't boot

[SanDiegoPC]

Been doing this for years & years now, and I now also do PC repair for a living ... but now I'm kinda stumped. Often I build computers outta spare parts (Just Another Box of Parts = JABOP) from repaired/refurb systems and I sell them on Craig'sList. They are usually parts from upgrades on customer's PC's but this stuff actually came out of a machine I had here on my network until six months ago.

It's an Asus P5B motherboard & Nvidia AGP card. I'm using the video card in this box that was used with the motherboard when it was on our network. I have put new RAM in it and a new PSU. But we aren't getting any POST at all & no video.

I have swapped out the AGP card and had same problem. Even tried a PCI video card that I know works. No video.

Here's the kicker: No beeps either. Just to verify the speaker was working, I removed the RAM and hit the button. Sure enough, it beeped to indicate no RAM. Pulled the video card out of it and it made no sound when I hit the power. No beeps.

All of the fans work when I hit the power: CPU, Case fan 1 in front, case fan 2 in rear, and the power supply fan. I know I'm getting power. The 4-pin 12V connector on the motherboard is connected.

What do I do next? I know this board & CPU worked, as I said, six months ago when I pulled them from that computer back then.

 

[MagnusTheBrewer]

Two things, even though the board and CPU worked six months ago, there is no guarantee they are working now. And second, while I appreciate your experience, sometimes you have to go back to basics. A minimal install outside the box with one stick of ram.

 

[SanDiegoPC]

Two things, even though the board and CPU worked six months ago, there is no guarantee they are working now. And second, while I appreciate your experience, sometimes you have to go back to basics. A minimal install outside the box with one stick of ram.

You are correct on both counts - good call on the 'outside build' as that is the direction I'm heading. I am careful with electronics - esp. PC parts because I use them 60 hours a week and am always needing ~something.~

But just b/c I've been careful with something doesn't mean it's still any good.

 

[SanDiegoPC]

Turned out to be the RAM. I took the motherboard outta the case & had the same reaction - none. I took the RAM out & reinstalled it. I had one 1MB DIMM in bank one, and one in bank 2. The board wanted them both to be in bank 1. I thought I was making the intelligent choice, originally, matching two slots of the same color: Yellow. But using one yellow and one black slot, both bank 1, the computer boots just fine. Go figure!

 

[john3850]

On this motherboard sockets 1 and 3 are yellow and sockets 2 and 4 are black. Configuring DDR2 dual channel on this motherboard is pretty easy: just install each module on a socket with the same color.
Your PC now boots but I bet it is now in single channel.

 

[SanDiegoPC]

On this motherboard sockets 1 and 3 are yellow and sockets 2 and 4 are black. Configuring DDR2 dual channel on this motherboard is pretty easy: just install each module on a socket with the same color.
Your PC now boots but I bet it is now in single channel.

Yes but it wouldn't boot at all with both sticks in the yellow slots, as I originally had them.