Cannot ping my vista computer- Calibre Companion wont work

My desktop is running Vista (64-bit). It is directly connected to router (Linksys WRT160N) which is connected to the cable modem. My son's computer is connected wirelessly. I can ping his computer but he can not ping mine.

I am trying to wirelessly connect my android tablet to my desktop to use the calibre-Companion app. The Calibre Library is on my Vista desktop.

No firewalls are currently running. Norton Security Suite has been uninstalled. I wont be able to use the calibre-Companion app until I can get any device to communicate properly with my desktop.
any suggestions??

Try removing the ethernet adapter from device management and rebooting your computer. After the reboot it will reinstall the driver and then try to reconnect to the internet. If you are lucky it will ask you what kind of connection do you want. Select home network. Also are you trying to ping by name or ipaddress? If by name try ipaddress.