Where can you purchase RAM for a Compaq Presario 5BW130 desktop?

The Compaq Presario 5BW130 desktop supports a maximum of 512 MB of RAM using two 256 MB PC100/PC133 SDRAM modules. These modules aren't carried on the sites of most major online retailers, but can easily be purchased on eBay. A reference retailer can be found below.

Note that for guaranteed compatibility, you should purchase "low density" modules. High density modules are cheaper, but aren't compatible with all systems (especially those with Intel chipsets) and tend to be slower.