Questions about ram memory replacment

[Guest]

what type of ram memory replacement should I get for my computer? I have a emachines model W3644

 

[strangestranger]

http://www.emachines.com/products/products.html?prod=W3644

1024MB 667MHz DDR2 dual-channel memory (2 × 512MB)
Expandable to 2GB
2 DDR2 slots total, 0 DDR2 slots available

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