Installing more ram

[Durnberg]

I recently purchased 1 gig or ram and installed it. I had 512 (2x256). If I try to boot with all the RAM installed the computer won't boot and I don't hear any POST. All the RAM is DDR400 so I thought it would be compatible, I am however able to boot with the 1 gig stick in and one of the two 256 mb sticks and it reads that I have 1.2 gb RAM installed. Any ideas on why I can't boot with both 256 mb sticks in there? What can I do to get that second one in there?

Thanks in advance.

Black and red Scorpio 868 gaming case 500W Power Supply
Asus A8V Deluxe
AMD 64 3000+ CPU
ATI 9600 pro 256 MB
80GB FAST SATA 150 Hard Drive with 8MB Cache
250 GB Maxtor ATA + 40 Maxtor ATA
LG 16X DVD Burner, Dual Layer DVD+/-/Ram
Soundblaster Audigy 1
10/100 Yukon Fast LAN (onboard)
Windows XP (32bit)

 

[cwiz]

your ram is probably dual channel, you need 2 identical sticks of ram. i would recommend getting another 1 gig stick

 

[Trifid]

Try different order of RAM (e.g. same sizes with same colour DIMM slots, or other way round with different sized sticks in same colour.

 

[Durnberg]

your ram is probably dual channel, you need 2 identical sticks of ram. i would recommend getting another 1 gig stick

I considered that but the 1 gb stick and one of the 2 256 sticks works so doesn't that kind of defeat that theory?

I have reseated them a few different times in different slots but I plan on trying again once I get home from work.

 

[McHopsky]

Sometimes RAM combinations dont work. Ages ago I had 2 x 256 and then I bought a 512 stick. When I tried to put the 3 sticks in there, it wouldnt recognize it as 1gig, but as 768. Look at your motherboard manual and itll tell you what combinations are compatable with eachother. My advice to you is to sell (or return) your two 256's and buy another gig of ram.