First, try setting a static ip address on her laptop that is within the correct range for the router she wants to connect to. For example, if the router address is 192.168.2.1 then set her static ip for the wireless card to something like 192.168.2.200 (a higher number is better to avoid conflicts, but the highest usable value is usually x.x.x.254).
(I have included instructions for setting a static ip address, just in case you need them, at the bottom of my message)
If a static ip allows the connection to work, then there is a problem with DHCP on either the network or her laptop. It may be that there are no available ip addresses in the DHCP range to issue her laptop. Or, it may be that the DHCP client service on her laptop is not running, although that is unlikely since she can connect elsewhere.
If the static ip DOESN'T fix the problem, it may be an issue with the security key that is entered for the network on her laptop. First be sure her laptop is compatible with the type of encryption used by the network (if any). Some cards cannot connect to networks using newer encryption such as some WPA/WPA2. Make sure the security key entered on her system is correct and that the connection is set to use the correct encryption. For example, if her card is set up to use WEP but the network uses WPA encryption, she won't be able to connect.
Ideally, she should be able to connect using DHCP (a non-static or dynamic ip address).
Also, if you set a static ip address, be sure to change the settings back to their original settings when you are finished. Ideally, they should be set to "Obtain automatically."
(Instructions for setting a static ip address, if necessary)
Go to Start>Run... type "ncpa.cpl" without quotes in the run box, then click "OK." In the Network Connections window, right click the wireless network connection and go to properties. In the center box of the connection properties window, double click the words "Internet Protocol (TCP/IP)" to open the IP properties window. In this window, there should be a series of boxes each with 3 periods in them. Click the circle next to "Use the following IP address" to select that option. If anything is filled into these boxes before you enter anything, copy it down before changing it. The first box should be the desired, static IP address for her laptop as discussed above. The second box should usually be filled with 255.255.255.0 and the last box should be the ip address of the router. You will also have to specify a DNS server in one of the lower two boxes at the very bottom of the window. You should be able to use the router's ip address for this as well. Click "OK" on all property windows and repair the connection (right-click the wireless connection icon and go to "repair").
(end of static ip explanation)
