new memory no go...HELP!!!

hi all,

i have an asus a7v600 mobo (c. 2003 - socket a - AMD xp3000+ processor) with the via kt600 chipset, flashed to the latest bios (1008).

it has three double data rate dimm sockets.

i formerly had 2 512mb pc2100 ddr dimms (i can't determine the brand) in sockets 1 and 3 (if i tried any other permutation, all i got on boot up was the post code for no or bad memory)

i decided to upgrade my memory, so i went out a bought 2 1gb pc3200 dimms.

i removed the old memory, and popped the new stuff in.

but it won't work...unless it's a single DIMM in socket 3.

i tried every permutation:

DIMMS in 1-3
DIMMS in 1-2
DIMMS in 2-3

i tried all those again after reducing the memory speed from auto (which I think is 400) to 333. once again, no go unless i just had one DIMM in socket 3.

now on the asus site, in the troubleshooting section, there's post (in stilted english) that states the a7v600 supports 2 1gb sticks of DDR PC3200. my mobo manual, though, has a table with a few brands of memory on it, including samsung (which is the new stuff i bought), but only up to 512. that table is titled DDR 400 one DIMM support only. there's another table called DDR 400 two DIMM support only, which has 4 more brands of ram (once again, only up to 512mb).

i also found a document on-line for socket 754 mobo (the replacement for the socket a) that ran a down a bunch of memory permutations for that board. in it, it talks about 2 different types of ddr ram dimms: x8 single rank or x16 and x8 double rank.

so i have two questions:
1) as per above, which type of ram do i have (my samsung sticks have 8 chips aside); on the chips the number is k4h510838d; on a sticker on the stick the number is m368l2923dun-ccc?
2) does anyone know any more tricks i haven't tried (since my next step is taking the DIMM back and spending the money on something more worthwhile...like the world of warcraft expansion...hehehehe).

sorry for the long post, but i'm a little frustrated!

thanks!

steve