Question: Why I cannot access Internet with good wireless signal strength?
Just wonder why cannot access Internet with good wireless signal strength on wireless network? Actually, connected to wireless network and having good wireless signal strength doesn’t confirm you can access Internet, you should type following command in command prompt (cmd.exe) to make sure your computer have correct IP, netmask, gateway and DNS servers configured. If not correct, you won't be able to access Internet.
If you can ping the network gateway but fail to access any website, most probably you have domain/URL resolving problem. You should check whether you have correct DNS servers configured. If not, you can try following free DNS servers provided by OpenDNS.
If you need further helps, take a look on this wireless network setup tutorial.