I "downgraded" her laptop to XP and it still was not able to connect to her modem. She power cycled it again and still no link lights; the old laptop however can still connect without a problem.
To try and troubleshot this further we sent a switch home with her (more of a distant hope, as we don't have a router to let her try) and she was able to get a link light on the modem and switch and then connect the laptop to the switch and get a link light there, but to no avail. At this point my end user is extremely frustrated (understandably so). Her ISP says that the laptop needs a NIC driver (i've checked, and rechecked, and checked again to make sure that it has the most up to date NIC driver).
Today I'm going to take her laptop home with me and see if I can get it to have any issues on my home network and troubleshoot the problem from there. Really the only possibility I can see from this point is letting her try one of my personal routers and seeing if having something with DCHP between the modem and her new laptop does the trick. I, clearely, need to learn more about networking.
Thanks for the help!