i have a desktop connectd by LAN(ethernet card) to server which cannot
connect to internet. so installed a usb adapter to connect to wirelss router,
Now wireless adapter will not connect to internet when the ethernet card is
not disabled.

Go to Control Panel and Internet options. Now go to the Connections Tab and
at the bottom is Lan settings. Click on that. When that opens, put a tick in
the box next to "Automatically detect settings" and now click OK twice and
then close control panel. Try to get to internet again now.

Wireless Network Connection Unable to obtain IP
Wireless network stops working
Strange errors in my D-Link DI-634M router log today
Wireless network Win XP Pro - Win2k Pro
My intermal wifi card cannot find my linksys router
wireless switch
Wireless network on a w98
Network on XP Home
WiFi infrastructure/ad-hoc mode?
Computers in same room see different networks