Server memory in my desktop, doesn't work, why??

So I got my hands on some spare memory from work, i got the following:

*HP 4gb (2gb x 2) pc3200, ddr 400, cl3, ecc, reg
*HP 3gb (1gb x 3) pc3200, ddr 400 (no markings, but i assume its ecc, reg also)
*Dell (Netlist) 3gb (1gb x 3) pc2100, ddr 266, cl 2.5, (no markings, but i assume its ecc, reg also)

So I put it in my MSI K7t 266pro 2 server and she doesn't post and just beeps once, pause, beeps again, pause, and beeps again, and on and on.....Its a VERY faint beep also...So i thought maybe the motherboard couldn't take it, So I put it into my Asus P4P800e Deluxe motherboard, SAME thing, no post or anything. What is up with this? Is there a setting int he bios I have to adjust to use this memory? I would hate to have to buy memory. Post away..

ecc memory doesnt work in regular desktop boards, sorry to say.

you could sell it, and buy some stuff that works.

Is there a motherboard I could buy for my Amd Athlon XP 2600+ that can use ECC memory? Thanks..OR can you recomend me a motherboard that can use ECC Reg memory that supports that AMD X2 3800+? I would rather spend some change on a faster cpu/motherboard that will support this memory then buying a motherboard that supports this memory and use my old athalon xp 2600+ Let me know, thanks.

EDIT: I found this, and I think it supports ECC memory from a site I was looking at, does it support REG & ECC memory?

http://www.newegg.com/Product/Product.aspx?Item=N82E16813127234

Here are the specs from Abit's site:

http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=311

You will have to go to a server grade board to use ECC and unless you are running tight thresh hold apps or database stuff the ECC wont do much for you.

If you look into building a server, I would keep the memory but otherwise, sell it in the classies if you can see it (cant yet it looks like), Ebay or Craigslist.

Yea, I am building a server, which is why I want to use it. I am thinking about getting a motherboard that supports 8gb so that I could use the (2) 2gb and the (2) 1gb for a total of 6gb of ram, I know its OVER kill, but can you suggest a motherboard that does socket 393 for that X2 3800+ and supports ECC/REG ram, 8gb of it..What do you think about the above motherboard? ECC Yes, but not sure about REG.

EDIT: I think the above motherboard wont work....non buffered = non registered i think. That supports ECC/non registered....ideas?