Wireless Networking

[Tom]

Just installed my netgear wireless network hardware but
only one of my computers actually works and can access
the internet while the other one says it has found a
wireless network, gets assigned an ip from my router
correctly but cannot ping anything on the network or
access the internet? Any reccomendations like shall i
format it and start again or i am told there is possibly
a setting about 802.11 i need to change?

Thanx for any help