Wireless Problems  

You may have to connect the laptop to the router with a cord the first time. Just disconnect the cord from your mother in law's computer and connect it to the laptop. When my stepson got his laptop we already had a wireless router in the house and he had to connect via the cord the first time that computer accessed the internet through our connection. After that his wireless connection worked fine.

Configure the IF address if you are able to get from the service provider ,otherwise set the IP address to " Obtain IP address automatically". To access this wnidow, open the network connection and in the network connections, right click on the WLAN connection(or wireless network connection)and click on properties and you will get the properties window. Here you select the TCP/IP protocol.Then click on again the properties tab after selecting the TCP/IP. Here select the radio button for 'obtain the IP address automatically'. This may work .

check to make sure the laptop does not have an ipadress static, ot a proxy server. If that is the case i would take the router out of the picture and hard wire to connection. Then add the router after that. I find when do a new router install install to a pc, the best thing is to power them all down bring up cable modem, router, the n power on PC. Good luck

LOL I don't have much knowledge on this , I have a broadband internet connection from BSNL India, the modem is wireless, means 7 computers can work from it at the same time, my son has hooked the3 computers in our home through LAN, another laptop he too uses in the lawn
I think you should try some thing similar in your country
Thanks for this nice post. keep sharing, happy posting, cheers
ARUN