I recently bought a small tower computer (Here) that said it takes DDR3 Ram, so I bought this ram off of amazon.com (here). However, when it arrived it was a third the size of the ram it should be replacing, and does not fit. Does the computer not take DDR3 Ram? Are there multiple sizes of Ram? Is the product on amazon wrong? Thanks for any light you could shine on this :/

I recently bought a small tower computer (Dell OptiPlex, Intel Core 2 Duo 2.9GHz E7500 Processor, 4GB Memory, 160GB Hard Drive, DVD, Windows 10 Home, WiFi) that said it takes DDR3 RAM, so I bought this RAM off of Amazon.com (Samsung 2GB PC-8500 DDR3 1066MHz SO-DIMM 204 Pin 2.0GB Memory Upgrade Modules M471B5673FH0-CF8). 

However, when it arrived it was a third the size of the ram it should be replacing, and does not fit. Does the computer not take DDR3 Ram? Are there multiple sizes of RAM? Is the product listing on Amazon wrong?

Pictures for reference below.