Design
The Elitebook 2540p has a scratch-proof lid made out of anodised aluminium; its screen is held by metal hinges; and it even meets military specifications (MIL-STD 810G) for vibration, dust, humidity, temperature and altitude. (You'll apparently have no problem using it at 24,300 metres, as long as you're wearing a space suit.)
It looks the same as the HP Elitebook 2530p, but there are some differences in the ventilation and the placement of ports. The right side of the chassis shows the most evolution, as it now has a combined microphone and headphone port (instead of two individual ports), and a USB port has been removed in order to make way for a DisplayPort. Furthermore, the air vents, which used to be located on the underside of the laptop, now stretch all the way up the right side, allowing more air to escape.