If it has no RCA or phono, ie "unbalanced" inputs, you can't use just your laptop with them. Buy something like an M-Audio USB interface - essentially a USB DAC-ADC (ie, input-analog to digital/output-digital to analog converter) that has XLR outputs, these tend to be cheaper than USB input DACs with balanced outputs marketed as Hi-Fi equipment. They will look more like a control panel than a classy aluminum fascia on your desk but just think of the savings - HiFi stuff don't have entry-level units with balanced connections.
I saw the other thread - you can just return them and get the Audioengine A5. The whole point with Audioengine is that they make passive speakers that are a no-brainer for mainstream users - ie, you don't really need to be a recording professional or Hi-Fi enthusiast to use* or enjoy** them.
*RCA and 3.5mm phono inputs)
**"dark" sound means you won't put up with a studio monitor revealing each and every sharp note played back from a few feet from your head