lan settings for ibm lenovo thinkpad

hello every one. i am in need of desperate help to try to connect to the internet on my lenovo thinkpad. i have an hp pavilion a6240a running windows 7. i have a 320GB 3G hard drive. my laptop is operating on windows xp professional, my pc is connected to a thomson gateway modem. i have found and switched on the wireless radio settings 100%on the laptop. every time i turn on the laptop, it ( connects ) me automatically. i am getting a message telling me i am connected to the internet, with a 100% percent signal and the (LAN )wireless network is also showing it is connected with a 100% signal. when i try to open up internet explorer i am told, " this page cannot be shown, would u like to connect or stay off line. i have typed in the address of the gateway, 10.0.0.138 which should open up the thomson gateway page. i have also tried typing in bigpond.com the bar at the bottom goes thru all the green digits and then done but i can't even get that on internet explorer. i have gone into tools and internet options to set up a home network. still nothing. i have even connected the gateway direct to the computer. still nothing. i know it is a configuration problem but as a relative newby, 5 yrs using computers when i did not even know how to turn one on 5 yrs ago. i am also classed as a senior australian. at 64 yrs old and not even a tafe computer course to learn the basics, i have picked up the using the computer by cramming all the information that i can, simply by sitting for hours at the computer and using the software installed to learn how to use it. could some-one please advise what i am doing wrong. i just want to connect the lenovo by using the LAN settings. i know/hope it will be something simple. i do a lot of voluntary work with the ages and dis-abled. i bought the laptop so that i can take it with me to record the needs of the people that i help. hope u can help me guys. regards, cathy