Hi there
Does the wireless adaptor get an IP address from the AP? if it does it may be a DNS problem. Check under Network Connections that the wireless adaptor has not been "Bridge" to any other network connection. Try changing the SSID on the AP so you can create a new profile on your PC just in case it is holding on to any old information. Does the AP have a switch? if so make sure the PC will work with a straight ethernet connection.

Good Luck
Dale