Laptop not recognizing memory

I just received a used laptop from a buddy of mine. Its a Toshiba Satellite that came loaded with a single 512k stick. I read the Toshiba site, as well as other sites indicating that this machine will shupport up to 2g ram. (Vista home edition).

So, I go by 2x1g sticks of ram, install, reboot. The machine is only recognizing 1g. Thinking I had a bad stick, I removed both. rebooted with just one and it was fine, swapped them, rebooted, it was fine. So essentially it will see only 1 of the sticks, not both at the same time.

So - any ideas on how to resolve this?