If you have dial-up then the ethernet should be of no concern to you, dial-up does not use the Ethernet Settings to connect to the internet, HOWEVER.
The problem she COULD be having could be for 1 of two reasons.
1. The phone number she's using is not for her area
OR
2. The connection is simply too slow.
If 1 is the case, then she should try multiple numbers for the dial-up until 1 works well enough
If 2 is the case then I suggest she gets an accelerator that compresses images and other graphics so that the pages load faster.
Another problem is a bit more technical but it might be that the ISPs Nameservers aren't working properly, in which case you'd have to consult with them to see if her area is having problems.
In any case the best thing to do either way is to consult with your ISP, USUALLY they can help (albeit sometimes the solution is only temporary.)