Laptop unable to access Internet Via Wi-Fi

Hey all, I am not a rookie in the networking of Windows XP or anything but this problem I am having with a customers Emachines laptop its puzzling me.

Whats currently installed on the laptop.
Windows XP home Sp2 with all current updates
FreeAVG 7.5
Xoft Spy
Windows Defender
Ad-Aware
etrust Pest Control

There is no 3rd party firewall.... only running the windows firewall.

The problem is that the laptop is on a wireless network. Now the laptop can browse the network fine but when it comes to surfing the internet or doing anything involving the internet it will not. The customer has a desktop unit on the same network hooked up the same way via wireless.... This unit can surf the network and internet with no problems. The laptop was working a week ago but then one night they were using it and the wireless at random disconnected and well since that it hasnt been able to surf the internet. I asked them to take the laptop to school and try using their wireless they provide and the same results.... So this tells me its not their router not allowing internet access to the laptop but its something within th laptop.... No hardware or software changes have been made by the customer. This problem is puzzling me as I have never seen this type networking error before. I plan to uninstall the drivers for the internal wireless card and re-installing them, if that doesnt work I am going to hook it up to a wired network and see what happens. the wi-fi needs to be resolved so i can jsut have the wired working only......

Has anyone ever seen this networking problem before? Any idea what could have caused this or whats causing this problem?