Windows 7 - Work Offline Message when exiting Hibernation

For the last week or so when I restart from Hibernation, I get a "Work Offline" message even though I am connected to the Internet. It tells me there is no connection to the Internet and gives me a choice of 'Work Offline' or 'Try Again'. It dissapears after clicking on 'Try Again' 2 to 3 times.

If I click 'Work Offline', then click on my Gmail account (which is active online), I get a "Webpage unavailable while offline" message. I chose 'Connect' and finally I get onto my Gmail site.

I forgot to mention that this is occuring on a HP Laptop using Windows 7 Home Premium and a D-Link WIFI router.

Any suggestions? Thanks

Try this,go to
Control Panel>Device Manager>Network Adapters>Right clickyour network adapter>Properties>Power Management>untick where it says Allow this computer to turn this device of to save power