Why does my computer certificate my run into?

i own installed 1 gig of knock against and another with 256 of run into. my motherboard said that the newly installed push (1 gig) would be compatible but on my computer, it says i enjoy only 256 mb of hit. when i did an analysis of my computer it said..
256 Megabytes Installed Memory

Slot 'A0' has 256 MB
Slot 'A1' have 1024 MB

Answer:
Remove the 256MB stick and move the 1GB stick to slot "A0".

Your system should see the new RAM. If not, help yourself to it back.

Then, try installing the 256MB stick to slot "A1". Your system should see the new RAM. If not, leave it out, in that IS a compatibility issue.
Is this DDR ram? DDR2? Put the 1 Gig within the 0 slot,(the slot nearest the cpu, see if it boots up. NO? There's your answer.
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