|I'd do more testing on the network adapter. They do go out but it is rare. |
A $4 usb to ethernet might be the most easy repair is the adapter is actually bad. Which I really doubt. More of a chance the settings are wrong.
As above other types are out there such as pcmcia/pccard and maybe even traditional slot type of cards.
Wireless should be used when no wired solution exists.
"Best Practices", Event viewer, host file, perfmon, are in my top 10