First question, what brand of router is she using? Don't be like
my cousin, use 3Com and kena screwed up by Singnet.
If she's using Singnet and 3Com, ask her to login to her router and
try these settings:
VPI/VCI - 0/100
How the ISP connects - PPPoA
Username - [email protected] (replace whatever with her
username)
Encapsulation - VC MUX
IP address - assigned by ISP
Using other routers, ask her reset everything. Either there is a
reset button, or if none is present, most likely is hold the power
button for a few seconds. Or if possible, reset the router via a
browser, meaning logging in to the router.