That looks like an interesting solution, the problem is that what if he can't connect to the internet at all?
1) he can't download it to that computer (I know he can dl to a thumb drive on a different computer)
2) but if he does that - the program can't connect to the internet anyhow to manage the driver download.
What you need to do:
on the Lenovo:
go to 'control panel' 'device manager', find the unknown ethernet device, right click it, then 'properties'.
This will pull up the dialog for the specific device. Click the 'details' tab, then in the drop down selection box, pull up 'hardware ids'. Write down that long string, then on a different computer with internet access (hopefully you have that), do a google search for that string. That should pull up some results that tell you what specific piece of hardware you have (ie: intel pro wireless 10/100/100, or centrino wireless n, atheros blah blah blah).
From there, go to the manufacturers website and you should be able to find drivers for the particular hardware. From there, download them to a thumb drive, then install it and see if that doesn't work.
If it does, then you can try the slim drivers program listed above to manage the rest of your drivers.