Hi,
On some motherboards there is a setting in CMOS that causes the system to rebuild itself, and then it will declare all memory correctly.
Also did you totally disconnect the power i.e. plug the plug before inseting the memory.

>I added 1GB to my system.
>At boot, POST shows 2048MB.
>
>But System Info" shows only 1024MB.
>
>Should I be worried?... Feels like I should be.
>
>cheers