Connection

Yes I have a suggestion, here is what you need to do.
1 Make sure your new router is connected to the Ethernet port on the DSL/Cable Modem, you never specified which type of modem you have, if I knew this information I could assist you even more accurately. Your PC should be connected to the new router also on one of the Ehternet ports, they usually have 4. You need to verify your computer (PC) is getting the DHCP information from the new Router(Linksys) This can easily be determined using this command in az DOS window. If you are using Windows XP, again you did not specify your PC's OS, go to "Start", then "Run" and type in "cmd", withouth the quotes.
This will open a DOS window. In this window type "ipconfig /all"
The important thing to look for here is your Network cards IP Address, Default Gateway, Primary and Secondary Domain Servers Addresses. These should nearly match your daughters information, except for the IP address, whcih will be close but the last number(s) will be different. Most of the time the problem is due to both the modem and the router are on the same network and are both running DHCP, which is what gives out the IP address, default gateway and DNS information for your PC and your Daughters to use for Internet access. It could also be that your PC has the same IP address as her's, whcih will cause the exact problem you are discribing as well. If you turn off her laptop and can then access the Internet on your PC, then this is exactly what is happening. You will then need to make sure the Linksys Router and the DSL/Cable Modem are on a different network, by changing the address of one or the other, it is easiest for you to probably just change the Router. It is problably set to 192.168.1.1 or 192.168.0.1 Hook your PC directly into the modem again. run the command "ipconfig /all" and look at the IP address it gives your PC. If this is the same as the one your Router is giving, then you have found your problem. Unplug from the modem an again plug straight into the router, nothing else. Open a web browser and type in http://192.168.x.x whatever the IP address is for the default gateway that is shown on your PC. You should get a login window. By default Linksys usually uses admin as the username and password, consult your manual to be certain. In the web page that opens, your manual can help you further here as well, there should be a "Setup" link you can click where you can change the "LAN" network IP Address. You only need to change the 3rd number, as in 192.168."X".1 If the modem was 192.168.1.0 for example change the Routher to 192.168.2.0 and you should be fine. Please let me know if this has helped or if you need further assistance.