Vista has many problems. You might want to upgrade your OS and use a newer version like windows 7. I will offer you some solutions.
1) make sure your firewall is turn off.
2) Reset your router and try to see if your windows laptop can connect to the laptop
3) make sure you wifi card is installed properly, if not re install your wi fi card again. Update all drivers.
4) make sure your wi fi is turn off. At the side of th laptop there should have a switch to turn off and on the wi fi.
5) try connecting to your router again but this time use an ethernet cable.
6) check your network settings.
One last time can you access the internet. Does your wi fi shows connected but cannot access internet or your wifi shows not connected to thr network.