Low or No Connectivity to wireless router.

The signal is good to very good on the wireless adapter for desktop.
Because of Low or no connectivity, the desktop won't connect to the wireless router to open the internet.
I have checked internet connections. I have put it as "automatically detect" for Windows XP to figure it out. It is not working.
I have Adelpia Cable connection which is connected to the wireless router.
Thanks
Sampath

 

What are the IP addresses of the desktop PC and the router?

 

Try this:

1) Go to Network Connections.
2) Right-click on Wireless Network Connection, select Properties.
3) Click on 'Wireless Networks' tab.
4) In 'Preferred Networks', click on Add button.
5) Enter SSID, set Network Authentication for Open, Shared, WPA, or WPA-PSK.
5) Set Data Encryption type.
6) If your Wireless Access Point has a encryption key (HIGHLY RECOMMENDED) take check off of 'The key is provided for me automatically' and enter Network Key. Re-enter key in 'Confirm network key'.
7) Click OK.
8) Back in 'Wireless Networks' tab, click on 'Advanced' button. Select 'Access Point (infrastructure) networks only.