I need to update the encryption settings on my SIL's Verizon router. She is still using WEP. Does the router have to be connected to her PC when I do this? Put another way, can I bring her router to my house, connect it to my Verizon Ethernet, configure it (WPA2 settings, network name and password) and then take it back to her house and simply connect it there? I assume I can NOT do this because my IP address is different. Thanks.

PS Yes, I know it would be easier to just do it at her house but I have my reasons for asking.Think I have found the answer. Every Verizon router (at least the particular model we have) has the same IP address. The various devices which connect to that router are assigned their own IP address. So, it looks like the router can be configured from any PC. I will confirm that tomorrow. Here is what I discovered. I can configure the router from a different PC but each router is specific to Verizon Ethernet. So, I can get a strong WiFi signal but no connection to the internet.Please GIVE more details about your setup.
Name of the ISP (Internet Service Provider)  and what kind of modem they provided. Is the modem also a router?
What BRAND and model of wireless router, if any,  do you use?
Did your ISP provide specific information about security settings?
Example: One provider needs the MAC address of the  main computer used  in your house or office. If not present, the connection will fail. This is a security measure.

One one time everything was working good?
Then you made a change and is became unreliable?

BTW, it is  important to tell if you reusing a older OS or something other than Windows. SOMETIMES the OS itself does not support a security protocol.

Verizon is our ISP. We both have Actiontec MI424-WR routers. She never upgraded from the original WEP encryption. I upgraded her to WPA2 and assigned a username/password for her router and WPA2 key for her network. She was not having any issues related to the old encryption, but coincidentally she just (yesterday) BEGAN having problems connecting to the internet from her iPad 2 although she says her old iPhone 4 connected fine (maybe she thought she was connected to WiFi but really it was 3G). She also has a Netgear 2000RPT extender. I rebooted/reconfigured extender and everything seems to be working fine. Yes, Verizon gives detailed router settings. We both have Win 7 Home Edition.

When I connected my router to her system, my iPad found and connected to the WiFi network fine but it would not connect to the internet. Since the router "Internet On" light was orange instead of green, I assumed the problem was not within the router but rather her Verizon main box was not recognizing my router.

Bottom line is you can configure these Verizon routers from any PC but they will not connect to the Internet from any PC.