Wireless network stops working in XP until reconnect

I have rather strange issue with my wireless connection. Once in a while my computer just breaks all the internet connections and couldn't connect anywhere else. It does not however get disconnected from the network. Taking wireless connection down and then up again restores internet access but nothing else does. Other computer connected to the same wireless router works all the time.

So how can I diagnose what's happening and fix it?

The computer isn't going into sleep/power saving mode and then not properly restoring the wireless card when it awakes is it? I've seen this happen before.

Purposely put the computer into sleep/power saving mode to see if you can make it fail.

If that is the case, right click on the device in Control Panel -> System -> Hardware -> Advanced -> Device Manager -> Network Adapters -> Your Network Card

then choose the Power Management tab and try unticking the "Allow computer to turn off this device to save power" option

Can you still ping your router when you're disconnected from the internet. Do start run cmd and type ping If you can try doing pathping www.google.com this should tell you where the break between you and the internet is.