I have seen a few cases with the new HP Elitebook 2530P. The default Windows PE builds do not have the latest Windows Vista driver for this and it must be updated. The driver necessary is the latest from Intel, version 13.1.2 or later. Here is a link:
I posted this as a heads-up because these machines will not boot to either PC-DOS or MS-DOS with the latest DOS drivers for the network card (version 13.1.2 as well, as of this post. Versions of the NDIS2 after 13.1.2 may work, but the latest Vista driver is necessary as of this post.