Windows 7: Problem with Wireless network Connection

Hello All,
I bought a Lenovo Thinkpad T410 with Windows 7 Professional on 64bit as OS like a week ago. I set up the wireless connection to my home network and it was working fine till last night... This morning I had a problem connecting to the same wireless network.. It found the network but unable to connect .... I tried to delete the existing networks through Network Sharing Center --> Manage Wireless Networks and added our home network again..It says "Wireless network connection has invalid IP Address".. and not working... But my roommate's laptop with XP as OS is connecting to our home network and working...

Please help me how to fix this issue.

Thanks

It might be helpful to reset the TCP-IP stack which sometimes can fix this problem.

1. 
   At the command prompt, copy and paste (or type) the following command and then press ENTER:
2. netsh int ip reset c:\resetlog.txt
   Note If you do not want to specify a directory path for the log file, use the following command: netsh int ip reset resetlog.txt
3. Reboot the computer.