Connecting Macbook to Dell U2312HM Monitor

That monitor has Displayport and DVI ports. Not knowing your age of MacBook it is hard to say what connector you can use.

Go to System Profiler and lookup your machine identifier.

It should say something like MacBook 4,1.

For these models, you'll need both the cables linked below from Apple and Staples:

MacBook 1,1 through 4,x and 5,2 use a mini-DVI connector and will not directly connect audio to it.

http://store.apple.com/us/product/M9321G/B/apple-mini-dvi-to-dvi-adapter

http://www.staples.com/office/supplies/StaplesProductDisplay?storeId=10001&catal ogIdentifier=2&partNumber=972599

For these Macs, use the cable linked to below their machine identifer:

5,1 and 6,1 have mini-Displayport connector but no audio directly over it.

7,1 has audio over mini-Displayport.

http://www.cablesforless.com/15-Foot-Mini-DisplayPort-to-HDMI-Cable-P7063.aspx

USB connectivity on the display may not work, unless you can find a cable that includes USB support with the other ports. Often dual link connectors have USB cable support, and are more expensive.

Note: If you have an Air or Pro, please specify that as the connectors are different for those models.