Currently no Windows 8 Wi-Fi drivers for Elitebook 2740p are available. You have to wait for some time until they are released. For the time being, you can download Windows 7 drives instead and try to install on Windows 8. Follow the link given below from where you can download Windows 7 Wi-Fi drivers for this product. http://h20000.www2.hp.com/bizsupport/TechSupport/ProductList.jsp?lang=en&cc=us&taskId=135&prodTypeId=5169094&prodSeriesId=4145567
Ensure that you have backed up your important data before trying installing the drivers.
Note: Windows 7 Wi-Fi drivers may or may not work on Windows 8.
Hope this helps.